mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-21 15:12:02 +00:00
Consistency fixups
This commit is contained in:
Robert Schulze
parent
082d639043
commit
3bdd4a5173
@ -5,7 +5,15 @@ sidebar_position: 102
|
||||
|
||||
# any
|
||||
|
||||
Selects the first encountered value of a column, ignoring any `NULL` values.
|
||||
Selects the first encountered value of a column.
|
||||
|
||||
:::warning
|
||||
As a query can be executed in arbitrary order, the result of this function is non-deterministic.
|
||||
If you need an arbitrary but deterministic result, use functions [`min`](../reference/min.md) or [`max`](../reference/max.md).
|
||||
:::
|
||||
|
||||
By default, the function never returns NULL, i.e. ignores NULL values in the input column.
|
||||
However, if the function is used with the `RESPECT NULLS` modifier, it returns the first value reads no matter if NULL or not.
|
||||
|
||||
**Syntax**
|
||||
|
||||
@ -13,44 +21,47 @@ Selects the first encountered value of a column, ignoring any `NULL` values.
|
||||
any(column) [RESPECT NULLS]
|
||||
```
|
||||
|
||||
Aliases: `any_value`, [`first_value`](../reference/first_value.md).
|
||||
Aliases `any(column)` (without `RESPECT NULLS`)
|
||||
- `any_value`
|
||||
- [`first_value`](../reference/first_value.md).
|
||||
|
||||
Alias for `any(column) RESPECT NULLS`
|
||||
- `anyRespectNulls`, `any_respect_nulls`
|
||||
- `firstValueRespectNulls`, `first_value_respect_nulls`
|
||||
- `anyValueRespectNulls`, `any_value_respect_nulls`
|
||||
|
||||
**Parameters**
|
||||
- `column`: The column name.
|
||||
|
||||
**Returned value**
|
||||
|
||||
:::note
|
||||
By default, the `anyLast` function never returns `NULL`. However, it supports the `RESPECT NULLS` modifier after the function name. Using this modifier will ensure the function selects the first value passed, regardless of whether it is `NULL` or not.
|
||||
|
||||
Alias: `anyRespectNulls`
|
||||
:::
|
||||
The first value encountered.
|
||||
|
||||
:::note
|
||||
The return type of the function is the same as the input, except for LowCardinality which is discarded. This means that given no rows as input it will return the default value of that type (0 for integers, or Null for a Nullable() column). You might use the `-OrNull` [combinator](../../../sql-reference/aggregate-functions/combinators.md) ) to modify this behaviour.
|
||||
:::
|
||||
|
||||
:::warning
|
||||
The query can be executed in any order and even in a different order each time, so the result of this function is indeterminate.
|
||||
To get a determinate result, you can use the [`min`](../reference/min.md) or [`max`](../reference/max.md) function instead of `any`.
|
||||
The return type of the function is the same as the input, except for LowCardinality which is discarded.
|
||||
This means that given no rows as input it will return the default value of that type (0 for integers, or Null for a Nullable() column).
|
||||
You might use the `-OrNull` [combinator](../../../sql-reference/aggregate-functions/combinators.md) ) to modify this behaviour.
|
||||
:::
|
||||
|
||||
**Implementation details**
|
||||
|
||||
In some cases, you can rely on the order of execution. This applies to cases when `SELECT` comes from a subquery that uses `ORDER BY`.
|
||||
In some cases, you can rely on the order of execution.
|
||||
This applies to cases when `SELECT` comes from a subquery that uses `ORDER BY`.
|
||||
|
||||
When a `SELECT` query has the `GROUP BY` clause or at least one aggregate function, ClickHouse (in contrast to MySQL) requires that all expressions in the `SELECT`, `HAVING`, and `ORDER BY` clauses be calculated from keys or from aggregate functions. In other words, each column selected from the table must be used either in keys or inside aggregate functions. To get behavior like in MySQL, you can put the other columns in the `any` aggregate function.
|
||||
When a `SELECT` query has the `GROUP BY` clause or at least one aggregate function, ClickHouse (in contrast to MySQL) requires that all expressions in the `SELECT`, `HAVING`, and `ORDER BY` clauses be calculated from keys or from aggregate functions.
|
||||
In other words, each column selected from the table must be used either in keys or inside aggregate functions.
|
||||
To get behavior like in MySQL, you can put the other columns in the `any` aggregate function.
|
||||
|
||||
**Example**
|
||||
|
||||
Query:
|
||||
|
||||
```sql
|
||||
CREATE TABLE any_nulls (city Nullable(String)) ENGINE=Log;
|
||||
CREATE TABLE tab (city Nullable(String)) ENGINE=Memory;
|
||||
|
||||
INSERT INTO any_nulls (city) VALUES (NULL), ('Amsterdam'), ('New York'), ('Tokyo'), ('Valencia'), (NULL);
|
||||
INSERT INTO tab (city) VALUES (NULL), ('Amsterdam'), ('New York'), ('Tokyo'), ('Valencia'), (NULL);
|
||||
|
||||
SELECT any(city), anyRespectNulls(city) FROM any_nulls;
|
||||
SELECT any(city), anyRespectNulls(city) FROM tab;
|
||||
```
|
||||
|
||||
```response
|
||||
|
||||
@ -5,7 +5,15 @@ sidebar_position: 105
|
||||
|
||||
# anyLast
|
||||
|
||||
Selects the last value encountered, ignoring any `NULL` values by default. The result is just as indeterminate as for the [any](../../../sql-reference/aggregate-functions/reference/any.md) function.
|
||||
Selects the last encountered value of a column.
|
||||
|
||||
:::warning
|
||||
As a query can be executed in arbitrary order, the result of this function is non-deterministic.
|
||||
If you need an arbitrary but deterministic result, use functions [`min`](../reference/min.md) or [`max`](../reference/max.md).
|
||||
:::
|
||||
|
||||
By default, the function never returns NULL, i.e. ignores NULL values in the input column.
|
||||
However, if the function is used with the `RESPECT NULLS` modifier, it returns the first value reads no matter if NULL or not.
|
||||
|
||||
**Syntax**
|
||||
|
||||
@ -13,16 +21,16 @@ Selects the last value encountered, ignoring any `NULL` values by default. The r
|
||||
anyLast(column) [RESPECT NULLS]
|
||||
```
|
||||
|
||||
Alias `anyLast(column)` (without `RESPECT NULLS`)
|
||||
- [`last_value`](../reference/last_value.md).
|
||||
|
||||
Aliases for `anyLast(column) RESPECT NULLS`
|
||||
- `anyLastRespectNulls`, `anyLast_respect_nulls`
|
||||
- `lastValueRespectNulls`, `last_value_respect_nulls`
|
||||
|
||||
**Parameters**
|
||||
- `column`: The column name.
|
||||
|
||||
:::note
|
||||
|
||||
By default, the `anyLast` function never returns `NULL`. However, it supports the `RESPECT NULLS `modifier after the function name, which will ensure the function selects the last value passed, regardless of whether it is `NULL` or not.
|
||||
|
||||
Alias: `anyLastRespectNulls`
|
||||
:::
|
||||
|
||||
**Returned value**
|
||||
|
||||
- The last value encountered.
|
||||
@ -32,11 +40,11 @@ Alias: `anyLastRespectNulls`
|
||||
Query:
|
||||
|
||||
```sql
|
||||
CREATE TABLE any_last_nulls (city Nullable(String)) ENGINE=Log;
|
||||
CREATE TABLE tab (city Nullable(String)) ENGINE=Memory;
|
||||
|
||||
INSERT INTO any_last_nulls (city) VALUES ('Amsterdam'),(NULL),('New York'),('Tokyo'),('Valencia'),(NULL);
|
||||
INSERT INTO tab (city) VALUES ('Amsterdam'),(NULL),('New York'),('Tokyo'),('Valencia'),(NULL);
|
||||
|
||||
SELECT anyLast(city), anyLastRespectNulls(city) FROM any_last_nulls;
|
||||
SELECT anyLast(city), anyLastRespectNulls(city) FROM tab;
|
||||
```
|
||||
|
||||
```response
|
||||
|
||||
@ -221,14 +221,15 @@ void registerAggregateFunctionsAnyRespectNulls(AggregateFunctionFactory & factor
|
||||
= {.returns_default_when_only_null = false, .is_order_dependent = true, .is_window_function = true};
|
||||
|
||||
factory.registerFunction("any_respect_nulls", {createAggregateFunctionAnyRespectNulls, default_properties_for_respect_nulls});
|
||||
factory.registerAlias("any_value_respect_nulls", "any_respect_nulls", AggregateFunctionFactory::Case::Insensitive);
|
||||
factory.registerAlias("first_value_respect_nulls", "any_respect_nulls", AggregateFunctionFactory::Case::Insensitive);
|
||||
factory.registerAlias("anyRespectNulls", "any_respect_nulls", AggregateFunctionFactory::Case::Sensitive);
|
||||
factory.registerAlias("first_value_respect_nulls", "any_respect_nulls", AggregateFunctionFactory::Case::Insensitive);
|
||||
factory.registerAlias("firstValueRespectNulls", "any_respect_nulls", AggregateFunctionFactory::Case::Sensitive);
|
||||
factory.registerAlias("any_value_respect_nulls", "any_respect_nulls", AggregateFunctionFactory::Case::Insensitive);
|
||||
factory.registerAlias("anyValueRespectNulls", "any_respect_nulls", AggregateFunctionFactory::Case::Sensitive);
|
||||
|
||||
factory.registerFunction("anyLast_respect_nulls", {createAggregateFunctionAnyLastRespectNulls, default_properties_for_respect_nulls});
|
||||
factory.registerAlias("last_value_respect_nulls", "anyLast_respect_nulls", AggregateFunctionFactory::Case::Insensitive);
|
||||
factory.registerAlias("anyLastRespectNulls", "anyLast_respect_nulls", AggregateFunctionFactory::Case::Sensitive);
|
||||
factory.registerAlias("last_value_respect_nulls", "anyLast_respect_nulls", AggregateFunctionFactory::Case::Insensitive);
|
||||
factory.registerAlias("lastValueRespectNulls", "anyLast_respect_nulls", AggregateFunctionFactory::Case::Sensitive);
|
||||
|
||||
/// Must happen after registering any and anyLast
|
||||
|
||||
@ -1,18 +1,28 @@
|
||||
anyRespectNulls
|
||||
0
|
||||
\N
|
||||
\N
|
||||
0
|
||||
6
|
||||
4
|
||||
\N
|
||||
\N
|
||||
0
|
||||
9
|
||||
firstValueRespectNulls
|
||||
0
|
||||
\N
|
||||
\N
|
||||
0
|
||||
6
|
||||
anyValueRespectNulls
|
||||
0
|
||||
\N
|
||||
\N
|
||||
0
|
||||
6
|
||||
lastValueRespectNulls
|
||||
4
|
||||
\N
|
||||
\N
|
||||
0
|
||||
9
|
||||
anyLastRespectNulls
|
||||
4
|
||||
\N
|
||||
\N
|
||||
|
||||
@ -1,28 +1,40 @@
|
||||
-- Tests aliases of any and anyLast functions
|
||||
|
||||
-- anyRespectNulls
|
||||
SELECT anyRespectNulls(number) from numbers(5);
|
||||
-- aliases of any
|
||||
|
||||
SELECT 'anyRespectNulls';
|
||||
SELECT anyRespectNulls(number) FROM numbers(5);
|
||||
SELECT arrayReduce('anyRespectNulls', [NULL, 10]::Array(Nullable(UInt8)));
|
||||
SELECT anyRespectNullsMerge(t) FROM (SELECT anyRespectNullsState(NULL::Nullable(UInt8)) as t FROM numbers(5));
|
||||
SELECT finalizeAggregation(CAST(unhex('01'), 'AggregateFunction(anyRespectNulls, UInt64)'));
|
||||
SELECT anyRespectNullsIf (number, NOT isNull(number) AND (assumeNotNull(number) > 5)) FROM numbers(10);
|
||||
|
||||
-- anyLastRespectNulls
|
||||
SELECT anyLastRespectNulls(number) from numbers(5);
|
||||
SELECT arrayReduce('anyLastRespectNulls', [10, NULL]::Array(Nullable(UInt8)));
|
||||
SELECT anyLastRespectNullsMerge(t) FROM (SELECT anyLastRespectNullsState(NULL::Nullable(UInt8)) as t FROM numbers(5));
|
||||
SELECT finalizeAggregation(CAST(unhex('01'), 'AggregateFunction(anyLastRespectNulls, UInt64)'));
|
||||
SELECT anyLastRespectNullsIf (number, NOT isNull(number) AND (assumeNotNull(number) > 5)) FROM numbers(10);
|
||||
|
||||
-- firstValueRespectNulls
|
||||
SELECT firstValueRespectNulls(number) from numbers(5);
|
||||
SELECT 'firstValueRespectNulls';
|
||||
SELECT firstValueRespectNulls(number) FROM numbers(5);
|
||||
SELECT arrayReduce('firstValueRespectNulls', [NULL, 10]::Array(Nullable(UInt8)));
|
||||
SELECT firstValueRespectNullsMerge(t) FROM (SELECT firstValueRespectNullsState(NULL::Nullable(UInt8)) as t FROM numbers(5));
|
||||
SELECT finalizeAggregation(CAST(unhex('01'), 'AggregateFunction(firstValueRespectNulls, UInt64)'));
|
||||
SELECT firstValueRespectNullsIf (number, NOT isNull(number) AND (assumeNotNull(number) > 5)) FROM numbers(10);
|
||||
|
||||
-- lastValueRespectNulls
|
||||
SELECT lastValueRespectNulls(number) from numbers(5);
|
||||
SELECT 'anyValueRespectNulls';
|
||||
SELECT anyValueRespectNulls(number) FROM numbers(5);
|
||||
SELECT arrayReduce('anyValueRespectNulls', [NULL, 10]::Array(Nullable(UInt8)));
|
||||
SELECT anyValueRespectNullsMerge(t) FROM (SELECT anyValueRespectNullsState(NULL::Nullable(UInt8)) as t FROM numbers(5));
|
||||
SELECT finalizeAggregation(CAST(unhex('01'), 'AggregateFunction(anyValueRespectNulls, UInt64)'));
|
||||
SELECT anyValueRespectNullsIf (number, NOT isNull(number) AND (assumeNotNull(number) > 5)) FROM numbers(10);
|
||||
|
||||
-- aliases of anyLast
|
||||
|
||||
SELECT 'lastValueRespectNulls';
|
||||
SELECT lastValueRespectNulls(number) FROM numbers(5);
|
||||
SELECT arrayReduce('lastValueRespectNulls', [10, NULL]::Array(Nullable(UInt8)));
|
||||
SELECT lastValueRespectNullsMerge(t) FROM (SELECT lastValueRespectNullsState(NULL::Nullable(UInt8)) as t FROM numbers(5));
|
||||
SELECT finalizeAggregation(CAST(unhex('01'), 'AggregateFunction(lastValueRespectNulls, UInt64)'));
|
||||
SELECT lastValueRespectNullsIf (number, NOT isNull(number) AND (assumeNotNull(number) > 5)) FROM numbers(10);
|
||||
|
||||
SELECT 'anyLastRespectNulls';
|
||||
SELECT anyLastRespectNulls(number) FROM numbers(5);
|
||||
SELECT arrayReduce('anyLastRespectNulls', [10, NULL]::Array(Nullable(UInt8)));
|
||||
SELECT anyLastRespectNullsMerge(t) FROM (SELECT anyLastRespectNullsState(NULL::Nullable(UInt8)) as t FROM numbers(5));
|
||||
SELECT finalizeAggregation(CAST(unhex('01'), 'AggregateFunction(anyLastRespectNulls, UInt64)'));
|
||||
SELECT anyLastRespectNullsIf (number, NOT isNull(number) AND (assumeNotNull(number) > 5)) FROM numbers(10);
|
||||
|
||||
Loading…
Reference in New Issue
Block a user