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1362 lines
41 KiB
Markdown
1362 lines
41 KiB
Markdown
---
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slug: /en/sql-reference/functions/json-functions
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sidebar_position: 105
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sidebar_label: JSON
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---
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There are two sets of functions to parse JSON:
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- [`simpleJSON*` (`visitParam*`)](#simplejson-visitparam-functions) which is made for parsing a limited subset of JSON extremely fast.
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- [`JSONExtract*`](#jsonextract-functions) which is made for parsing ordinary JSON.
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## simpleJSON (visitParam) functions
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ClickHouse has special functions for working with simplified JSON. All these JSON functions are based on strong assumptions about what the JSON can be. They try to do as little as possible to get the job done as quickly as possible.
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The following assumptions are made:
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1. The field name (function argument) must be a constant.
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2. The field name is somehow canonically encoded in JSON. For example: `simpleJSONHas('{"abc":"def"}', 'abc') = 1`, but `simpleJSONHas('{"\\u0061\\u0062\\u0063":"def"}', 'abc') = 0`
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3. Fields are searched for on any nesting level, indiscriminately. If there are multiple matching fields, the first occurrence is used.
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4. The JSON does not have space characters outside of string literals.
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### simpleJSONHas
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Checks whether there is a field named `field_name`. The result is `UInt8`.
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**Syntax**
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```sql
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simpleJSONHas(json, field_name)
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```
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Alias: `visitParamHas`.
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**Parameters**
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- `json` — The JSON in which the field is searched for. [String](../data-types/string.md#string)
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- `field_name` — The name of the field to search for. [String literal](../syntax#string)
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**Returned value**
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- Returns `1` if the field exists, `0` otherwise. [UInt8](../data-types/int-uint.md).
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**Example**
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Query:
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```sql
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CREATE TABLE jsons
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(
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`json` String
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)
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ENGINE = Memory;
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INSERT INTO jsons VALUES ('{"foo":"true","qux":1}');
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SELECT simpleJSONHas(json, 'foo') FROM jsons;
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SELECT simpleJSONHas(json, 'bar') FROM jsons;
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```
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Result:
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```response
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1
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0
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```
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### simpleJSONExtractUInt
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Parses `UInt64` from the value of the field named `field_name`. If this is a string field, it tries to parse a number from the beginning of the string. If the field does not exist, or it exists but does not contain a number, it returns `0`.
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**Syntax**
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```sql
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simpleJSONExtractUInt(json, field_name)
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```
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Alias: `visitParamExtractUInt`.
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**Parameters**
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- `json` — The JSON in which the field is searched for. [String](../data-types/string.md#string)
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- `field_name` — The name of the field to search for. [String literal](../syntax#string)
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**Returned value**
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- Returns the number parsed from the field if the field exists and contains a number, `0` otherwise. [UInt64](../data-types/int-uint.md).
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**Example**
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Query:
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```sql
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CREATE TABLE jsons
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(
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`json` String
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)
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ENGINE = Memory;
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INSERT INTO jsons VALUES ('{"foo":"4e3"}');
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INSERT INTO jsons VALUES ('{"foo":3.4}');
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INSERT INTO jsons VALUES ('{"foo":5}');
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INSERT INTO jsons VALUES ('{"foo":"not1number"}');
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INSERT INTO jsons VALUES ('{"baz":2}');
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SELECT simpleJSONExtractUInt(json, 'foo') FROM jsons ORDER BY json;
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```
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Result:
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```response
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0
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4
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0
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3
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5
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```
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### simpleJSONExtractInt
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Parses `Int64` from the value of the field named `field_name`. If this is a string field, it tries to parse a number from the beginning of the string. If the field does not exist, or it exists but does not contain a number, it returns `0`.
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**Syntax**
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```sql
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simpleJSONExtractInt(json, field_name)
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```
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Alias: `visitParamExtractInt`.
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**Parameters**
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- `json` — The JSON in which the field is searched for. [String](../data-types/string.md#string)
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- `field_name` — The name of the field to search for. [String literal](../syntax#string)
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**Returned value**
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- Returns the number parsed from the field if the field exists and contains a number, `0` otherwise. [Int64](../data-types/int-uint.md).
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**Example**
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Query:
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```sql
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CREATE TABLE jsons
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(
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`json` String
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)
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ENGINE = Memory;
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INSERT INTO jsons VALUES ('{"foo":"-4e3"}');
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INSERT INTO jsons VALUES ('{"foo":-3.4}');
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INSERT INTO jsons VALUES ('{"foo":5}');
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INSERT INTO jsons VALUES ('{"foo":"not1number"}');
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INSERT INTO jsons VALUES ('{"baz":2}');
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SELECT simpleJSONExtractInt(json, 'foo') FROM jsons ORDER BY json;
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```
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Result:
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```response
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0
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-4
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0
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-3
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5
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```
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### simpleJSONExtractFloat
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Parses `Float64` from the value of the field named `field_name`. If this is a string field, it tries to parse a number from the beginning of the string. If the field does not exist, or it exists but does not contain a number, it returns `0`.
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**Syntax**
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```sql
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simpleJSONExtractFloat(json, field_name)
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```
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Alias: `visitParamExtractFloat`.
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**Parameters**
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- `json` — The JSON in which the field is searched for. [String](../data-types/string.md#string)
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- `field_name` — The name of the field to search for. [String literal](../syntax#string)
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**Returned value**
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- Returns the number parsed from the field if the field exists and contains a number, `0` otherwise. [Float64](../data-types/float.md/#float32-float64).
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**Example**
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Query:
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```sql
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CREATE TABLE jsons
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(
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`json` String
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)
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ENGINE = Memory;
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INSERT INTO jsons VALUES ('{"foo":"-4e3"}');
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INSERT INTO jsons VALUES ('{"foo":-3.4}');
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INSERT INTO jsons VALUES ('{"foo":5}');
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INSERT INTO jsons VALUES ('{"foo":"not1number"}');
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INSERT INTO jsons VALUES ('{"baz":2}');
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SELECT simpleJSONExtractFloat(json, 'foo') FROM jsons ORDER BY json;
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```
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Result:
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```response
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0
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-4000
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0
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-3.4
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5
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```
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### simpleJSONExtractBool
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Parses a true/false value from the value of the field named `field_name`. The result is `UInt8`.
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**Syntax**
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```sql
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simpleJSONExtractBool(json, field_name)
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```
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Alias: `visitParamExtractBool`.
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**Parameters**
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- `json` — The JSON in which the field is searched for. [String](../data-types/string.md#string)
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- `field_name` — The name of the field to search for. [String literal](../syntax#string)
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**Returned value**
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It returns `1` if the value of the field is `true`, `0` otherwise. This means this function will return `0` including (and not only) in the following cases:
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- If the field doesn't exists.
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- If the field contains `true` as a string, e.g.: `{"field":"true"}`.
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- If the field contains `1` as a numerical value.
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**Example**
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Query:
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```sql
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CREATE TABLE jsons
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(
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`json` String
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)
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ENGINE = Memory;
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INSERT INTO jsons VALUES ('{"foo":false,"bar":true}');
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INSERT INTO jsons VALUES ('{"foo":"true","qux":1}');
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SELECT simpleJSONExtractBool(json, 'bar') FROM jsons ORDER BY json;
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SELECT simpleJSONExtractBool(json, 'foo') FROM jsons ORDER BY json;
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```
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Result:
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```response
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0
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1
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0
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0
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```
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### simpleJSONExtractRaw
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Returns the value of the field named `field_name` as a `String`, including separators.
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**Syntax**
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```sql
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simpleJSONExtractRaw(json, field_name)
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```
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Alias: `visitParamExtractRaw`.
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**Parameters**
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- `json` — The JSON in which the field is searched for. [String](../data-types/string.md#string)
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- `field_name` — The name of the field to search for. [String literal](../syntax#string)
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**Returned value**
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- Returns the value of the field as a string, including separators if the field exists, or an empty string otherwise. [`String`](../data-types/string.md#string)
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**Example**
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Query:
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```sql
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CREATE TABLE jsons
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||
(
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`json` String
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)
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||
ENGINE = Memory;
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||
|
||
INSERT INTO jsons VALUES ('{"foo":"-4e3"}');
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INSERT INTO jsons VALUES ('{"foo":-3.4}');
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INSERT INTO jsons VALUES ('{"foo":5}');
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INSERT INTO jsons VALUES ('{"foo":{"def":[1,2,3]}}');
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INSERT INTO jsons VALUES ('{"baz":2}');
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SELECT simpleJSONExtractRaw(json, 'foo') FROM jsons ORDER BY json;
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```
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Result:
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```response
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"-4e3"
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-3.4
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5
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{"def":[1,2,3]}
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```
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### simpleJSONExtractString
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Parses `String` in double quotes from the value of the field named `field_name`.
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**Syntax**
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```sql
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simpleJSONExtractString(json, field_name)
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```
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Alias: `visitParamExtractString`.
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**Parameters**
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||
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- `json` — The JSON in which the field is searched for. [String](../data-types/string.md#string)
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- `field_name` — The name of the field to search for. [String literal](../syntax#string)
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**Returned value**
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- Returns the unescaped value of a field as a string, including separators. An empty string is returned if the field doesn't contain a double quoted string, if unescaping fails or if the field doesn't exist. [String](../data-types/string.md).
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**Implementation details**
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There is currently no support for code points in the format `\uXXXX\uYYYY` that are not from the basic multilingual plane (they are converted to CESU-8 instead of UTF-8).
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**Example**
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Query:
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|
||
```sql
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CREATE TABLE jsons
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(
|
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`json` String
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||
)
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ENGINE = Memory;
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||
|
||
INSERT INTO jsons VALUES ('{"foo":"\\n\\u0000"}');
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INSERT INTO jsons VALUES ('{"foo":"\\u263"}');
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INSERT INTO jsons VALUES ('{"foo":"\\u263a"}');
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INSERT INTO jsons VALUES ('{"foo":"hello}');
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SELECT simpleJSONExtractString(json, 'foo') FROM jsons ORDER BY json;
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```
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Result:
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||
```response
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\n\0
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||
☺
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||
|
||
```
|
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|
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## JSONExtract functions
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The following functions are based on [simdjson](https://github.com/lemire/simdjson), and designed for more complex JSON parsing requirements.
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|
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### isValidJSON
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Checks that passed string is valid JSON.
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**Syntax**
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||
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```sql
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isValidJSON(json)
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```
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||
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**Examples**
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||
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``` sql
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SELECT isValidJSON('{"a": "hello", "b": [-100, 200.0, 300]}') = 1
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SELECT isValidJSON('not a json') = 0
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```
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||
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### JSONHas
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If the value exists in the JSON document, `1` will be returned. If the value does not exist, `0` will be returned.
|
||
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**Syntax**
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||
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||
```sql
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JSONHas(json [, indices_or_keys]...)
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```
|
||
|
||
**Parameters**
|
||
|
||
- `json` — JSON string to parse. [String](../data-types/string.md).
|
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- `indices_or_keys` — A list of zero or more arguments, each of which can be either string or integer. [String](../data-types/string.md), [Int*](../data-types/int-uint.md).
|
||
|
||
`indices_or_keys` type:
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- String = access object member by key.
|
||
- Positive integer = access the n-th member/key from the beginning.
|
||
- Negative integer = access the n-th member/key from the end.
|
||
|
||
**Returned value**
|
||
|
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- Returns `1` if the value exists in `json`, otherwise `0`. [UInt8](../data-types/int-uint.md).
|
||
|
||
**Examples**
|
||
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Query:
|
||
|
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``` sql
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SELECT JSONHas('{"a": "hello", "b": [-100, 200.0, 300]}', 'b') = 1
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SELECT JSONHas('{"a": "hello", "b": [-100, 200.0, 300]}', 'b', 4) = 0
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||
```
|
||
|
||
The minimum index of the element is 1. Thus the element 0 does not exist. You may use integers to access both JSON arrays and JSON objects. For example:
|
||
|
||
``` sql
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SELECT JSONExtractKey('{"a": "hello", "b": [-100, 200.0, 300]}', 1) = 'a'
|
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SELECT JSONExtractKey('{"a": "hello", "b": [-100, 200.0, 300]}', 2) = 'b'
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SELECT JSONExtractKey('{"a": "hello", "b": [-100, 200.0, 300]}', -1) = 'b'
|
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SELECT JSONExtractKey('{"a": "hello", "b": [-100, 200.0, 300]}', -2) = 'a'
|
||
SELECT JSONExtractString('{"a": "hello", "b": [-100, 200.0, 300]}', 1) = 'hello'
|
||
```
|
||
|
||
### JSONLength
|
||
|
||
Return the length of a JSON array or a JSON object. If the value does not exist or has the wrong type, `0` will be returned.
|
||
|
||
**Syntax**
|
||
|
||
```sql
|
||
JSONLength(json [, indices_or_keys]...)
|
||
```
|
||
|
||
**Parameters**
|
||
|
||
- `json` — JSON string to parse. [String](../data-types/string.md).
|
||
- `indices_or_keys` — A list of zero or more arguments, each of which can be either string or integer. [String](../data-types/string.md), [Int*](../data-types/int-uint.md).
|
||
|
||
`indices_or_keys` type:
|
||
- String = access object member by key.
|
||
- Positive integer = access the n-th member/key from the beginning.
|
||
- Negative integer = access the n-th member/key from the end.
|
||
|
||
**Returned value**
|
||
|
||
- Returns the length of the JSON array or JSON object. Returns `0` if the value does not exist or has the wrong type. [UInt64](../data-types/int-uint.md).
|
||
|
||
**Examples**
|
||
|
||
``` sql
|
||
SELECT JSONLength('{"a": "hello", "b": [-100, 200.0, 300]}', 'b') = 3
|
||
SELECT JSONLength('{"a": "hello", "b": [-100, 200.0, 300]}') = 2
|
||
```
|
||
|
||
### JSONType
|
||
|
||
Return the type of a JSON value. If the value does not exist, `Null` will be returned.
|
||
|
||
**Syntax**
|
||
|
||
```sql
|
||
JSONType(json [, indices_or_keys]...)
|
||
```
|
||
|
||
**Parameters**
|
||
|
||
- `json` — JSON string to parse. [String](../data-types/string.md).
|
||
- `indices_or_keys` — A list of zero or more arguments, each of which can be either string or integer. [String](../data-types/string.md), [Int*](../data-types/int-uint.md).
|
||
|
||
`indices_or_keys` type:
|
||
- String = access object member by key.
|
||
- Positive integer = access the n-th member/key from the beginning.
|
||
- Negative integer = access the n-th member/key from the end.
|
||
|
||
**Returned value**
|
||
|
||
- Returns the type of a JSON value as a string, otherwise if the value doesn't exists it returns `Null`. [String](../data-types/string.md).
|
||
|
||
**Examples**
|
||
|
||
``` sql
|
||
SELECT JSONType('{"a": "hello", "b": [-100, 200.0, 300]}') = 'Object'
|
||
SELECT JSONType('{"a": "hello", "b": [-100, 200.0, 300]}', 'a') = 'String'
|
||
SELECT JSONType('{"a": "hello", "b": [-100, 200.0, 300]}', 'b') = 'Array'
|
||
```
|
||
|
||
### JSONExtractUInt
|
||
|
||
Parses JSON and extracts a value of UInt type.
|
||
|
||
**Syntax**
|
||
|
||
```sql
|
||
JSONExtractUInt(json [, indices_or_keys]...)
|
||
```
|
||
|
||
**Parameters**
|
||
|
||
- `json` — JSON string to parse. [String](../data-types/string.md).
|
||
- `indices_or_keys` — A list of zero or more arguments, each of which can be either string or integer. [String](../data-types/string.md), [Int*](../data-types/int-uint.md).
|
||
|
||
`indices_or_keys` type:
|
||
- String = access object member by key.
|
||
- Positive integer = access the n-th member/key from the beginning.
|
||
- Negative integer = access the n-th member/key from the end.
|
||
|
||
**Returned value**
|
||
|
||
- Returns a UInt value if it exists, otherwise it returns `Null`. [UInt64](../data-types/string.md).
|
||
|
||
**Examples**
|
||
|
||
Query:
|
||
|
||
``` sql
|
||
SELECT JSONExtractUInt('{"a": "hello", "b": [-100, 200.0, 300]}', 'b', -1) as x, toTypeName(x);
|
||
```
|
||
|
||
Result:
|
||
|
||
```response
|
||
┌───x─┬─toTypeName(x)─┐
|
||
│ 300 │ UInt64 │
|
||
└─────┴───────────────┘
|
||
```
|
||
|
||
### JSONExtractInt
|
||
|
||
Parses JSON and extracts a value of Int type.
|
||
|
||
**Syntax**
|
||
|
||
```sql
|
||
JSONExtractInt(json [, indices_or_keys]...)
|
||
```
|
||
|
||
**Parameters**
|
||
|
||
- `json` — JSON string to parse. [String](../data-types/string.md).
|
||
- `indices_or_keys` — A list of zero or more arguments, each of which can be either string or integer. [String](../data-types/string.md), [Int*](../data-types/int-uint.md).
|
||
|
||
`indices_or_keys` type:
|
||
- String = access object member by key.
|
||
- Positive integer = access the n-th member/key from the beginning.
|
||
- Negative integer = access the n-th member/key from the end.
|
||
|
||
**Returned value**
|
||
|
||
- Returns an Int value if it exists, otherwise it returns `Null`. [Int64](../data-types/int-uint.md).
|
||
|
||
**Examples**
|
||
|
||
Query:
|
||
|
||
``` sql
|
||
SELECT JSONExtractInt('{"a": "hello", "b": [-100, 200.0, 300]}', 'b', -1) as x, toTypeName(x);
|
||
```
|
||
|
||
Result:
|
||
|
||
```response
|
||
┌───x─┬─toTypeName(x)─┐
|
||
│ 300 │ Int64 │
|
||
└─────┴───────────────┘
|
||
```
|
||
|
||
### JSONExtractFloat
|
||
|
||
Parses JSON and extracts a value of Int type.
|
||
|
||
**Syntax**
|
||
|
||
```sql
|
||
JSONExtractFloat(json [, indices_or_keys]...)
|
||
```
|
||
|
||
**Parameters**
|
||
|
||
- `json` — JSON string to parse. [String](../data-types/string.md).
|
||
- `indices_or_keys` — A list of zero or more arguments, each of which can be either string or integer. [String](../data-types/string.md), [Int*](../data-types/int-uint.md).
|
||
|
||
`indices_or_keys` type:
|
||
- String = access object member by key.
|
||
- Positive integer = access the n-th member/key from the beginning.
|
||
- Negative integer = access the n-th member/key from the end.
|
||
|
||
**Returned value**
|
||
|
||
- Returns an Float value if it exists, otherwise it returns `Null`. [Float64](../data-types/float.md).
|
||
|
||
**Examples**
|
||
|
||
Query:
|
||
|
||
``` sql
|
||
SELECT JSONExtractFloat('{"a": "hello", "b": [-100, 200.0, 300]}', 'b', 2) as x, toTypeName(x);
|
||
```
|
||
|
||
Result:
|
||
|
||
```response
|
||
┌───x─┬─toTypeName(x)─┐
|
||
│ 200 │ Float64 │
|
||
└─────┴───────────────┘
|
||
```
|
||
|
||
### JSONExtractBool
|
||
|
||
Parses JSON and extracts a boolean value. If the value does not exist or has a wrong type, `0` will be returned.
|
||
|
||
**Syntax**
|
||
|
||
```sql
|
||
JSONExtractBool(json\[, indices_or_keys\]...)
|
||
```
|
||
|
||
**Parameters**
|
||
|
||
- `json` — JSON string to parse. [String](../data-types/string.md).
|
||
- `indices_or_keys` — A list of zero or more arguments, each of which can be either string or integer. [String](../data-types/string.md), [Int*](../data-types/int-uint.md).
|
||
|
||
`indices_or_keys` type:
|
||
- String = access object member by key.
|
||
- Positive integer = access the n-th member/key from the beginning.
|
||
- Negative integer = access the n-th member/key from the end.
|
||
|
||
**Returned value**
|
||
|
||
- Returns a Boolean value if it exists, otherwise it returns `0`. [Bool](../data-types/boolean.md).
|
||
|
||
**Example**
|
||
|
||
Query:
|
||
|
||
``` sql
|
||
SELECT JSONExtractBool('{"passed": true}', 'passed');
|
||
```
|
||
|
||
Result:
|
||
|
||
```response
|
||
┌─JSONExtractBool('{"passed": true}', 'passed')─┐
|
||
│ 1 │
|
||
└───────────────────────────────────────────────┘
|
||
```
|
||
|
||
### JSONExtractString
|
||
|
||
Parses JSON and extracts a string. This function is similar to [`visitParamExtractString`](#simplejsonextractstring) functions. If the value does not exist or has a wrong type, an empty string will be returned.
|
||
|
||
**Syntax**
|
||
|
||
```sql
|
||
JSONExtractString(json [, indices_or_keys]...)
|
||
```
|
||
|
||
**Parameters**
|
||
|
||
- `json` — JSON string to parse. [String](../data-types/string.md).
|
||
- `indices_or_keys` — A list of zero or more arguments, each of which can be either string or integer. [String](../data-types/string.md), [Int*](../data-types/int-uint.md).
|
||
|
||
`indices_or_keys` type:
|
||
- String = access object member by key.
|
||
- Positive integer = access the n-th member/key from the beginning.
|
||
- Negative integer = access the n-th member/key from the end.
|
||
|
||
**Returned value**
|
||
|
||
- Returns an unescaped string from `json`. If unescaping failed, if the value does not exist or if it has a wrong type then it returns an empty string. [String](../data-types/string.md).
|
||
|
||
**Examples**
|
||
|
||
``` sql
|
||
SELECT JSONExtractString('{"a": "hello", "b": [-100, 200.0, 300]}', 'a') = 'hello'
|
||
SELECT JSONExtractString('{"abc":"\\n\\u0000"}', 'abc') = '\n\0'
|
||
SELECT JSONExtractString('{"abc":"\\u263a"}', 'abc') = '☺'
|
||
SELECT JSONExtractString('{"abc":"\\u263"}', 'abc') = ''
|
||
SELECT JSONExtractString('{"abc":"hello}', 'abc') = ''
|
||
```
|
||
|
||
### JSONExtract
|
||
|
||
Parses JSON and extracts a value of the given ClickHouse data type. This function is a generalized version of the previous `JSONExtract<type>` functions. Meaning:
|
||
|
||
`JSONExtract(..., 'String')` returns exactly the same as `JSONExtractString()`,
|
||
`JSONExtract(..., 'Float64')` returns exactly the same as `JSONExtractFloat()`.
|
||
|
||
**Syntax**
|
||
|
||
```sql
|
||
JSONExtract(json [, indices_or_keys...], return_type)
|
||
```
|
||
|
||
**Parameters**
|
||
|
||
- `json` — JSON string to parse. [String](../data-types/string.md).
|
||
- `indices_or_keys` — A list of zero or more arguments, each of which can be either string or integer. [String](../data-types/string.md), [Int*](../data-types/int-uint.md).
|
||
- `return_type` — A string specifying the type of the value to extract. [String](../data-types/string.md).
|
||
|
||
`indices_or_keys` type:
|
||
- String = access object member by key.
|
||
- Positive integer = access the n-th member/key from the beginning.
|
||
- Negative integer = access the n-th member/key from the end.
|
||
|
||
**Returned value**
|
||
|
||
- Returns a value if it exists of the specified return type, otherwise it returns `0`, `Null`, or an empty-string depending on the specified return type. [UInt64](../data-types/int-uint.md), [Int64](../data-types/int-uint.md), [Float64](../data-types/float.md), [Bool](../data-types/boolean.md) or [String](../data-types/string.md).
|
||
|
||
**Examples**
|
||
|
||
``` sql
|
||
SELECT JSONExtract('{"a": "hello", "b": [-100, 200.0, 300]}', 'Tuple(String, Array(Float64))') = ('hello',[-100,200,300])
|
||
SELECT JSONExtract('{"a": "hello", "b": [-100, 200.0, 300]}', 'Tuple(b Array(Float64), a String)') = ([-100,200,300],'hello')
|
||
SELECT JSONExtract('{"a": "hello", "b": "world"}', 'Map(String, String)') = map('a', 'hello', 'b', 'world');
|
||
SELECT JSONExtract('{"a": "hello", "b": [-100, 200.0, 300]}', 'b', 'Array(Nullable(Int8))') = [-100, NULL, NULL]
|
||
SELECT JSONExtract('{"a": "hello", "b": [-100, 200.0, 300]}', 'b', 4, 'Nullable(Int64)') = NULL
|
||
SELECT JSONExtract('{"passed": true}', 'passed', 'UInt8') = 1
|
||
SELECT JSONExtract('{"day": "Thursday"}', 'day', 'Enum8(\'Sunday\' = 0, \'Monday\' = 1, \'Tuesday\' = 2, \'Wednesday\' = 3, \'Thursday\' = 4, \'Friday\' = 5, \'Saturday\' = 6)') = 'Thursday'
|
||
SELECT JSONExtract('{"day": 5}', 'day', 'Enum8(\'Sunday\' = 0, \'Monday\' = 1, \'Tuesday\' = 2, \'Wednesday\' = 3, \'Thursday\' = 4, \'Friday\' = 5, \'Saturday\' = 6)') = 'Friday'
|
||
```
|
||
|
||
### JSONExtractKeysAndValues
|
||
|
||
Parses key-value pairs from JSON where the values are of the given ClickHouse data type.
|
||
|
||
**Syntax**
|
||
|
||
```sql
|
||
JSONExtractKeysAndValues(json [, indices_or_keys...], value_type)
|
||
```
|
||
|
||
**Parameters**
|
||
|
||
- `json` — JSON string to parse. [String](../data-types/string.md).
|
||
- `indices_or_keys` — A list of zero or more arguments, each of which can be either string or integer. [String](../data-types/string.md), [Int*](../data-types/int-uint.md).
|
||
- `value_type` — A string specifying the type of the value to extract. [String](../data-types/string.md).
|
||
|
||
`indices_or_keys` type:
|
||
- String = access object member by key.
|
||
- Positive integer = access the n-th member/key from the beginning.
|
||
- Negative integer = access the n-th member/key from the end.
|
||
|
||
**Returned value**
|
||
|
||
- Returns an array of parsed key-value pairs. [Array](../data-types/array.md)([Tuple](../data-types/tuple.md)(`value_type`)).
|
||
|
||
**Example**
|
||
|
||
``` sql
|
||
SELECT JSONExtractKeysAndValues('{"x": {"a": 5, "b": 7, "c": 11}}', 'x', 'Int8') = [('a',5),('b',7),('c',11)];
|
||
```
|
||
|
||
### JSONExtractKeys
|
||
|
||
Parses a JSON string and extracts the keys.
|
||
|
||
**Syntax**
|
||
|
||
``` sql
|
||
JSONExtractKeys(json[, a, b, c...])
|
||
```
|
||
|
||
**Parameters**
|
||
|
||
- `json` — [String](../data-types/string.md) with valid JSON.
|
||
- `a, b, c...` — Comma-separated indices or keys that specify the path to the inner field in a nested JSON object. Each argument can be either a [String](../data-types/string.md) to get the field by the key or an [Integer](../data-types/int-uint.md) to get the N-th field (indexed from 1, negative integers count from the end). If not set, the whole JSON is parsed as the top-level object. Optional parameter.
|
||
|
||
**Returned value**
|
||
|
||
- Returns an array with the keys of the JSON. [Array](../data-types/array.md)([String](../data-types/string.md)).
|
||
|
||
**Example**
|
||
|
||
Query:
|
||
|
||
```sql
|
||
SELECT JSONExtractKeys('{"a": "hello", "b": [-100, 200.0, 300]}');
|
||
```
|
||
|
||
Result:
|
||
|
||
```
|
||
text
|
||
┌─JSONExtractKeys('{"a": "hello", "b": [-100, 200.0, 300]}')─┐
|
||
│ ['a','b'] │
|
||
└────────────────────────────────────────────────────────────┘
|
||
```
|
||
|
||
### JSONExtractRaw
|
||
|
||
Returns part of the JSON as an unparsed string. If the part does not exist or has the wrong type, an empty string will be returned.
|
||
|
||
**Syntax**
|
||
|
||
```sql
|
||
JSONExtractRaw(json [, indices_or_keys]...)
|
||
```
|
||
|
||
**Parameters**
|
||
|
||
- `json` — JSON string to parse. [String](../data-types/string.md).
|
||
- `indices_or_keys` — A list of zero or more arguments, each of which can be either string or integer. [String](../data-types/string.md), [Int*](../data-types/int-uint.md).
|
||
|
||
`indices_or_keys` type:
|
||
- String = access object member by key.
|
||
- Positive integer = access the n-th member/key from the beginning.
|
||
- Negative integer = access the n-th member/key from the end.
|
||
|
||
**Returned value**
|
||
|
||
- Returns part of the JSON as an unparsed string. If the part does not exist or has the wrong type, an empty string is returned. [String](../data-types/string.md).
|
||
|
||
**Example**
|
||
|
||
``` sql
|
||
SELECT JSONExtractRaw('{"a": "hello", "b": [-100, 200.0, 300]}', 'b') = '[-100, 200.0, 300]';
|
||
```
|
||
|
||
### JSONExtractArrayRaw
|
||
|
||
Returns an array with elements of JSON array, each represented as unparsed string. If the part does not exist or isn’t an array, then an empty array will be returned.
|
||
|
||
**Syntax**
|
||
|
||
```sql
|
||
JSONExtractArrayRaw(json [, indices_or_keys...])
|
||
```
|
||
|
||
**Parameters**
|
||
|
||
- `json` — JSON string to parse. [String](../data-types/string.md).
|
||
- `indices_or_keys` — A list of zero or more arguments, each of which can be either string or integer. [String](../data-types/string.md), [Int*](../data-types/int-uint.md).
|
||
|
||
`indices_or_keys` type:
|
||
- String = access object member by key.
|
||
- Positive integer = access the n-th member/key from the beginning.
|
||
- Negative integer = access the n-th member/key from the end.
|
||
|
||
**Returned value**
|
||
|
||
- Returns an array with elements of JSON array, each represented as unparsed string. Otherwise, an empty array is returned if the part does not exist or is not an array. [Array](../data-types/array.md)([String](../data-types/string.md)).
|
||
|
||
**Example**
|
||
|
||
```sql
|
||
SELECT JSONExtractArrayRaw('{"a": "hello", "b": [-100, 200.0, "hello"]}', 'b') = ['-100', '200.0', '"hello"'];
|
||
```
|
||
|
||
### JSONExtractKeysAndValuesRaw
|
||
|
||
Extracts raw data from a JSON object.
|
||
|
||
**Syntax**
|
||
|
||
``` sql
|
||
JSONExtractKeysAndValuesRaw(json[, p, a, t, h])
|
||
```
|
||
|
||
**Arguments**
|
||
|
||
- `json` — [String](../data-types/string.md) with valid JSON.
|
||
- `p, a, t, h` — Comma-separated indices or keys that specify the path to the inner field in a nested JSON object. Each argument can be either a [string](../data-types/string.md) to get the field by the key or an [integer](../data-types/int-uint.md) to get the N-th field (indexed from 1, negative integers count from the end). If not set, the whole JSON is parsed as the top-level object. Optional parameter.
|
||
|
||
**Returned values**
|
||
|
||
- Array with `('key', 'value')` tuples. Both tuple members are strings. [Array](../data-types/array.md)([Tuple](../data-types/tuple.md)([String](../data-types/string.md), [String](../data-types/string.md)).
|
||
- Empty array if the requested object does not exist, or input JSON is invalid. [Array](../data-types/array.md)([Tuple](../data-types/tuple.md)([String](../data-types/string.md), [String](../data-types/string.md)).
|
||
|
||
**Examples**
|
||
|
||
Query:
|
||
|
||
``` sql
|
||
SELECT JSONExtractKeysAndValuesRaw('{"a": [-100, 200.0], "b":{"c": {"d": "hello", "f": "world"}}}');
|
||
```
|
||
|
||
Result:
|
||
|
||
``` text
|
||
┌─JSONExtractKeysAndValuesRaw('{"a": [-100, 200.0], "b":{"c": {"d": "hello", "f": "world"}}}')─┐
|
||
│ [('a','[-100,200]'),('b','{"c":{"d":"hello","f":"world"}}')] │
|
||
└──────────────────────────────────────────────────────────────────────────────────────────────┘
|
||
```
|
||
|
||
Query:
|
||
|
||
``` sql
|
||
SELECT JSONExtractKeysAndValuesRaw('{"a": [-100, 200.0], "b":{"c": {"d": "hello", "f": "world"}}}', 'b');
|
||
```
|
||
|
||
Result:
|
||
|
||
``` text
|
||
┌─JSONExtractKeysAndValuesRaw('{"a": [-100, 200.0], "b":{"c": {"d": "hello", "f": "world"}}}', 'b')─┐
|
||
│ [('c','{"d":"hello","f":"world"}')] │
|
||
└───────────────────────────────────────────────────────────────────────────────────────────────────┘
|
||
```
|
||
|
||
Query:
|
||
|
||
``` sql
|
||
SELECT JSONExtractKeysAndValuesRaw('{"a": [-100, 200.0], "b":{"c": {"d": "hello", "f": "world"}}}', -1, 'c');
|
||
```
|
||
|
||
Result:
|
||
|
||
``` text
|
||
┌─JSONExtractKeysAndValuesRaw('{"a": [-100, 200.0], "b":{"c": {"d": "hello", "f": "world"}}}', -1, 'c')─┐
|
||
│ [('d','"hello"'),('f','"world"')] │
|
||
└───────────────────────────────────────────────────────────────────────────────────────────────────────┘
|
||
```
|
||
|
||
### JSON_EXISTS
|
||
|
||
If the value exists in the JSON document, `1` will be returned. If the value does not exist, `0` will be returned.
|
||
|
||
**Syntax**
|
||
|
||
```sql
|
||
JSON_EXISTS(json, path)
|
||
```
|
||
|
||
**Parameters**
|
||
|
||
- `json` — A string with valid JSON. [String](../data-types/string.md).
|
||
- `path` — A string representing the path. [String](../data-types/string.md).
|
||
|
||
:::note
|
||
Before version 21.11 the order of arguments was wrong, i.e. JSON_EXISTS(path, json)
|
||
:::
|
||
|
||
**Returned value**
|
||
|
||
- Returns `1` if the value exists in the JSON document, otherwise `0`.
|
||
|
||
**Examples**
|
||
|
||
``` sql
|
||
SELECT JSON_EXISTS('{"hello":1}', '$.hello');
|
||
SELECT JSON_EXISTS('{"hello":{"world":1}}', '$.hello.world');
|
||
SELECT JSON_EXISTS('{"hello":["world"]}', '$.hello[*]');
|
||
SELECT JSON_EXISTS('{"hello":["world"]}', '$.hello[0]');
|
||
```
|
||
|
||
### JSON_QUERY
|
||
|
||
Parses a JSON and extract a value as a JSON array or JSON object. If the value does not exist, an empty string will be returned.
|
||
|
||
**Syntax**
|
||
|
||
```sql
|
||
JSON_QUERY(json, path)
|
||
```
|
||
|
||
**Parameters**
|
||
|
||
- `json` — A string with valid JSON. [String](../data-types/string.md).
|
||
- `path` — A string representing the path. [String](../data-types/string.md).
|
||
|
||
:::note
|
||
Before version 21.11 the order of arguments was wrong, i.e. JSON_EXISTS(path, json)
|
||
:::
|
||
|
||
**Returned value**
|
||
|
||
- Returns the extracted value as a JSON array or JSON object. Otherwise it returns an empty string if the value does not exist. [String](../data-types/string.md).
|
||
|
||
**Example**
|
||
|
||
Query:
|
||
|
||
``` sql
|
||
SELECT JSON_QUERY('{"hello":"world"}', '$.hello');
|
||
SELECT JSON_QUERY('{"array":[[0, 1, 2, 3, 4, 5], [0, -1, -2, -3, -4, -5]]}', '$.array[*][0 to 2, 4]');
|
||
SELECT JSON_QUERY('{"hello":2}', '$.hello');
|
||
SELECT toTypeName(JSON_QUERY('{"hello":2}', '$.hello'));
|
||
```
|
||
|
||
Result:
|
||
|
||
``` text
|
||
["world"]
|
||
[0, 1, 4, 0, -1, -4]
|
||
[2]
|
||
String
|
||
```
|
||
|
||
### JSON_VALUE
|
||
|
||
Parses a JSON and extract a value as a JSON scalar. If the value does not exist, an empty string will be returned by default.
|
||
|
||
This function is controlled by the following settings:
|
||
|
||
- by SET `function_json_value_return_type_allow_nullable` = `true`, `NULL` will be returned. If the value is complex type (such as: struct, array, map), an empty string will be returned by default.
|
||
- by SET `function_json_value_return_type_allow_complex` = `true`, the complex value will be returned.
|
||
|
||
**Syntax**
|
||
|
||
```sql
|
||
JSON_VALUE(json, path)
|
||
```
|
||
|
||
**Parameters**
|
||
|
||
- `json` — A string with valid JSON. [String](../data-types/string.md).
|
||
- `path` — A string representing the path. [String](../data-types/string.md).
|
||
|
||
:::note
|
||
Before version 21.11 the order of arguments was wrong, i.e. JSON_EXISTS(path, json)
|
||
:::
|
||
|
||
**Returned value**
|
||
|
||
- Returns the extracted value as a JSON scalar if it exists, otherwise an empty string is returned. [String](../data-types/string.md).
|
||
|
||
**Example**
|
||
|
||
Query:
|
||
|
||
``` sql
|
||
SELECT JSON_VALUE('{"hello":"world"}', '$.hello');
|
||
SELECT JSON_VALUE('{"array":[[0, 1, 2, 3, 4, 5], [0, -1, -2, -3, -4, -5]]}', '$.array[*][0 to 2, 4]');
|
||
SELECT JSON_VALUE('{"hello":2}', '$.hello');
|
||
SELECT toTypeName(JSON_VALUE('{"hello":2}', '$.hello'));
|
||
select JSON_VALUE('{"hello":"world"}', '$.b') settings function_json_value_return_type_allow_nullable=true;
|
||
select JSON_VALUE('{"hello":{"world":"!"}}', '$.hello') settings function_json_value_return_type_allow_complex=true;
|
||
```
|
||
|
||
Result:
|
||
|
||
``` text
|
||
world
|
||
0
|
||
2
|
||
String
|
||
```
|
||
|
||
### toJSONString
|
||
|
||
Serializes a value to its JSON representation. Various data types and nested structures are supported.
|
||
64-bit [integers](../data-types/int-uint.md) or bigger (like `UInt64` or `Int128`) are enclosed in quotes by default. [output_format_json_quote_64bit_integers](../../operations/settings/settings.md#session_settings-output_format_json_quote_64bit_integers) controls this behavior.
|
||
Special values `NaN` and `inf` are replaced with `null`. Enable [output_format_json_quote_denormals](../../operations/settings/settings.md#settings-output_format_json_quote_denormals) setting to show them.
|
||
When serializing an [Enum](../data-types/enum.md) value, the function outputs its name.
|
||
|
||
**Syntax**
|
||
|
||
``` sql
|
||
toJSONString(value)
|
||
```
|
||
|
||
**Arguments**
|
||
|
||
- `value` — Value to serialize. Value may be of any data type.
|
||
|
||
**Returned value**
|
||
|
||
- JSON representation of the value. [String](../data-types/string.md).
|
||
|
||
**Example**
|
||
|
||
The first example shows serialization of a [Map](../data-types/map.md).
|
||
The second example shows some special values wrapped into a [Tuple](../data-types/tuple.md).
|
||
|
||
Query:
|
||
|
||
``` sql
|
||
SELECT toJSONString(map('key1', 1, 'key2', 2));
|
||
SELECT toJSONString(tuple(1.25, NULL, NaN, +inf, -inf, [])) SETTINGS output_format_json_quote_denormals = 1;
|
||
```
|
||
|
||
Result:
|
||
|
||
``` text
|
||
{"key1":1,"key2":2}
|
||
[1.25,null,"nan","inf","-inf",[]]
|
||
```
|
||
|
||
**See Also**
|
||
|
||
- [output_format_json_quote_64bit_integers](../../operations/settings/settings.md#session_settings-output_format_json_quote_64bit_integers)
|
||
- [output_format_json_quote_denormals](../../operations/settings/settings.md#settings-output_format_json_quote_denormals)
|
||
|
||
|
||
### JSONArrayLength
|
||
|
||
Returns the number of elements in the outermost JSON array. The function returns NULL if input JSON string is invalid.
|
||
|
||
**Syntax**
|
||
|
||
``` sql
|
||
JSONArrayLength(json)
|
||
```
|
||
|
||
Alias: `JSON_ARRAY_LENGTH(json)`.
|
||
|
||
**Arguments**
|
||
|
||
- `json` — [String](../data-types/string.md) with valid JSON.
|
||
|
||
**Returned value**
|
||
|
||
- If `json` is a valid JSON array string, returns the number of array elements, otherwise returns NULL. [Nullable(UInt64)](../data-types/int-uint.md).
|
||
|
||
**Example**
|
||
|
||
``` sql
|
||
SELECT
|
||
JSONArrayLength(''),
|
||
JSONArrayLength('[1,2,3]')
|
||
|
||
┌─JSONArrayLength('')─┬─JSONArrayLength('[1,2,3]')─┐
|
||
│ ᴺᵁᴸᴸ │ 3 │
|
||
└─────────────────────┴────────────────────────────┘
|
||
```
|
||
|
||
|
||
### jsonMergePatch
|
||
|
||
Returns the merged JSON object string which is formed by merging multiple JSON objects.
|
||
|
||
**Syntax**
|
||
|
||
``` sql
|
||
jsonMergePatch(json1, json2, ...)
|
||
```
|
||
|
||
**Arguments**
|
||
|
||
- `json` — [String](../data-types/string.md) with valid JSON.
|
||
|
||
**Returned value**
|
||
|
||
- If JSON object strings are valid, return the merged JSON object string. [String](../data-types/string.md).
|
||
|
||
**Example**
|
||
|
||
``` sql
|
||
SELECT jsonMergePatch('{"a":1}', '{"name": "joey"}', '{"name": "tom"}', '{"name": "zoey"}') AS res
|
||
|
||
┌─res───────────────────┐
|
||
│ {"a":1,"name":"zoey"} │
|
||
└───────────────────────┘
|
||
```
|
||
|
||
### JSONAllPaths
|
||
|
||
Returns the list of all paths stored in each row in [JSON](../data-types/newjson.md) column.
|
||
|
||
**Syntax**
|
||
|
||
``` sql
|
||
JSONAllPaths(json)
|
||
```
|
||
|
||
**Arguments**
|
||
|
||
- `json` — [JSON](../data-types/newjson.md).
|
||
|
||
**Returned value**
|
||
|
||
- An array of paths. [Array(String)](../data-types/array.md).
|
||
|
||
**Example**
|
||
|
||
``` sql
|
||
CREATE TABLE test (json JSON(max_dynamic_paths=1)) ENGINE = Memory;
|
||
INSERT INTO test FORMAT JSONEachRow {"json" : {"a" : 42}}, {"json" : {"b" : "Hello"}}, {"json" : {"a" : [1, 2, 3], "c" : "2020-01-01"}}
|
||
SELECT json, JSONAllPaths(json) FROM test;
|
||
```
|
||
|
||
```text
|
||
┌─json─────────────────────────────────┬─JSONAllPaths(json)─┐
|
||
│ {"a":"42"} │ ['a'] │
|
||
│ {"b":"Hello"} │ ['b'] │
|
||
│ {"a":["1","2","3"],"c":"2020-01-01"} │ ['a','c'] │
|
||
└──────────────────────────────────────┴────────────────────┘
|
||
```
|
||
|
||
### JSONAllPathsWithTypes
|
||
|
||
Returns the map of all paths and their data types stored in each row in [JSON](../data-types/newjson.md) column.
|
||
|
||
**Syntax**
|
||
|
||
``` sql
|
||
JSONAllPathsWithTypes(json)
|
||
```
|
||
|
||
**Arguments**
|
||
|
||
- `json` — [JSON](../data-types/newjson.md).
|
||
|
||
**Returned value**
|
||
|
||
- An array of paths. [Map(String, String)](../data-types/array.md).
|
||
|
||
**Example**
|
||
|
||
``` sql
|
||
CREATE TABLE test (json JSON(max_dynamic_paths=1)) ENGINE = Memory;
|
||
INSERT INTO test FORMAT JSONEachRow {"json" : {"a" : 42}}, {"json" : {"b" : "Hello"}}, {"json" : {"a" : [1, 2, 3], "c" : "2020-01-01"}}
|
||
SELECT json, JSONAllPathsWithTypes(json) FROM test;
|
||
```
|
||
|
||
```text
|
||
┌─json─────────────────────────────────┬─JSONAllPathsWithTypes(json)───────────────┐
|
||
│ {"a":"42"} │ {'a':'Int64'} │
|
||
│ {"b":"Hello"} │ {'b':'String'} │
|
||
│ {"a":["1","2","3"],"c":"2020-01-01"} │ {'a':'Array(Nullable(Int64))','c':'Date'} │
|
||
└──────────────────────────────────────┴───────────────────────────────────────────┘
|
||
```
|
||
|
||
### JSONDynamicPaths
|
||
|
||
Returns the list of dynamic paths that are stored as separate subcolumns in [JSON](../data-types/newjson.md) column.
|
||
|
||
**Syntax**
|
||
|
||
``` sql
|
||
JSONDynamicPaths(json)
|
||
```
|
||
|
||
**Arguments**
|
||
|
||
- `json` — [JSON](../data-types/newjson.md).
|
||
|
||
**Returned value**
|
||
|
||
- An array of paths. [Array(String)](../data-types/array.md).
|
||
|
||
**Example**
|
||
|
||
``` sql
|
||
CREATE TABLE test (json JSON(max_dynamic_paths=1)) ENGINE = Memory;
|
||
INSERT INTO test FORMAT JSONEachRow {"json" : {"a" : 42}}, {"json" : {"b" : "Hello"}}, {"json" : {"a" : [1, 2, 3], "c" : "2020-01-01"}}
|
||
SELECT json, JSONDynamicPaths(json) FROM test;
|
||
```
|
||
|
||
```text
|
||
┌─json─────────────────────────────────┬─JSONDynamicPaths(json)─┐
|
||
| {"a":"42"} │ ['a'] │
|
||
│ {"b":"Hello"} │ [] │
|
||
│ {"a":["1","2","3"],"c":"2020-01-01"} │ ['a'] │
|
||
└──────────────────────────────────────┴────────────────────────┘
|
||
```
|
||
|
||
### JSONDynamicPathsWithTypes
|
||
|
||
Returns the map of dynamic paths that are stored as separate subcolumns and their types in each row in [JSON](../data-types/newjson.md) column.
|
||
|
||
**Syntax**
|
||
|
||
``` sql
|
||
JSONAllPathsWithTypes(json)
|
||
```
|
||
|
||
**Arguments**
|
||
|
||
- `json` — [JSON](../data-types/newjson.md).
|
||
|
||
**Returned value**
|
||
|
||
- An array of paths. [Map(String, String)](../data-types/array.md).
|
||
|
||
**Example**
|
||
|
||
``` sql
|
||
CREATE TABLE test (json JSON(max_dynamic_paths=1)) ENGINE = Memory;
|
||
INSERT INTO test FORMAT JSONEachRow {"json" : {"a" : 42}}, {"json" : {"b" : "Hello"}}, {"json" : {"a" : [1, 2, 3], "c" : "2020-01-01"}}
|
||
SELECT json, JSONDynamicPathsWithTypes(json) FROM test;
|
||
```
|
||
|
||
```text
|
||
┌─json─────────────────────────────────┬─JSONDynamicPathsWithTypes(json)─┐
|
||
│ {"a":"42"} │ {'a':'Int64'} │
|
||
│ {"b":"Hello"} │ {} │
|
||
│ {"a":["1","2","3"],"c":"2020-01-01"} │ {'a':'Array(Nullable(Int64))'} │
|
||
└──────────────────────────────────────┴─────────────────────────────────┘
|
||
```
|
||
|
||
### JSONSharedDataPaths
|
||
|
||
Returns the list of paths that are stored in shared data structure in [JSON](../data-types/newjson.md) column.
|
||
|
||
**Syntax**
|
||
|
||
``` sql
|
||
JSONSharedDataPaths(json)
|
||
```
|
||
|
||
**Arguments**
|
||
|
||
- `json` — [JSON](../data-types/newjson.md).
|
||
|
||
**Returned value**
|
||
|
||
- An array of paths. [Array(String)](../data-types/array.md).
|
||
|
||
**Example**
|
||
|
||
``` sql
|
||
CREATE TABLE test (json JSON(max_dynamic_paths=1)) ENGINE = Memory;
|
||
INSERT INTO test FORMAT JSONEachRow {"json" : {"a" : 42}}, {"json" : {"b" : "Hello"}}, {"json" : {"a" : [1, 2, 3], "c" : "2020-01-01"}}
|
||
SELECT json, JSONSharedDataPaths(json) FROM test;
|
||
```
|
||
|
||
```text
|
||
┌─json─────────────────────────────────┬─JSONSharedDataPaths(json)─┐
|
||
│ {"a":"42"} │ [] │
|
||
│ {"b":"Hello"} │ ['b'] │
|
||
│ {"a":["1","2","3"],"c":"2020-01-01"} │ ['c'] │
|
||
└──────────────────────────────────────┴───────────────────────────┘
|
||
```
|
||
|
||
### JSONSharedDataPathsWithTypes
|
||
|
||
Returns the map of paths that are stored in shared data structure and their types in each row in [JSON](../data-types/newjson.md) column.
|
||
|
||
**Syntax**
|
||
|
||
``` sql
|
||
JSONSharedDataPathsWithTypes(json)
|
||
```
|
||
|
||
**Arguments**
|
||
|
||
- `json` — [JSON](../data-types/newjson.md).
|
||
|
||
**Returned value**
|
||
|
||
- An array of paths. [Map(String, String)](../data-types/array.md).
|
||
|
||
**Example**
|
||
|
||
``` sql
|
||
CREATE TABLE test (json JSON(max_dynamic_paths=1)) ENGINE = Memory;
|
||
INSERT INTO test FORMAT JSONEachRow {"json" : {"a" : 42}}, {"json" : {"b" : "Hello"}}, {"json" : {"a" : [1, 2, 3], "c" : "2020-01-01"}}
|
||
SELECT json, JSONSharedDataPathsWithTypes(json) FROM test;
|
||
```
|
||
|
||
```text
|
||
┌─json─────────────────────────────────┬─JSONSharedDataPathsWithTypes(json)─┐
|
||
│ {"a":"42"} │ {} │
|
||
│ {"b":"Hello"} │ {'b':'String'} │
|
||
│ {"a":["1","2","3"],"c":"2020-01-01"} │ {'c':'Date'} │
|
||
└──────────────────────────────────────┴────────────────────────────────────┘
|
||
```
|