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145
docs/en/sql-reference/functions/string-replace-functions.md
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@ -8,6 +8,78 @@ sidebar_label: Replacing in Strings
[General strings functions](string-functions.md) and [functions for searching in strings](string-search-functions.md) are described separately.
## overlay
Replace part of the string `input` with another string `replace`, starting at the 1-based index `offset`.
**Syntax**
```sql
overlay(s, replace, offset[, length])
```
**Parameters**
- `input`: A string type [String](../data-types/string.md).
- `replace`: A string type [String](../data-types/string.md).
- `offset`: An integer type [Int](../data-types/int-uint.md). If `offset` is negative, it is counted from the end of the `input` string.
- `length`: Optional. An integer type [Int](../data-types/int-uint.md). `length` specifies the length of the snippet within input to be replaced. If `length` is not specified, the number of bytes removed from `input` equals the length of `replace`; otherwise `length` bytes are removed.
**Returned value**
- A [String](../data-types/string.md) data type value.
**Example**
```sql
SELECT overlay('ClickHouse SQL', 'CORE', 12) AS res;
```
Result:
```text
┌─res─────────────┐
│ ClickHouse CORE │
└─────────────────┘
```
## overlayUTF8
Replace part of the string `input` with another string `replace`, starting at the 1-based index `offset`.
Assumes that the string contains valid UTF-8 encoded text. If this assumption is violated, no exception is thrown and the result is undefined.
**Syntax**
```sql
overlayUTF8(s, replace, offset[, length])
```
**Parameters**
- `s`: A string type [String](../data-types/string.md).
- `replace`: A string type [String](../data-types/string.md).
- `offset`: An integer type [Int](../data-types/int-uint.md). If `offset` is negative, it is counted from the end of the `input` string.
- `length`: Optional. An integer type [Int](../data-types/int-uint.md). `length` specifies the length of the snippet within input to be replaced. If `length` is not specified, the number of characters removed from `input` equals the length of `replace`; otherwise `length` characters are removed.
**Returned value**
- A [String](../data-types/string.md) data type value.
**Example**
```sql
SELECT overlayUTF8('ClickHouse是一款OLAP数据库', '开源', 12, 2) AS res;
```
Result:
```text
┌─res────────────────────────┐
│ ClickHouse是开源OLAP数据库 │
└────────────────────────────┘
```
## replaceOne
Replaces the first occurrence of the substring `pattern` in `haystack` by the `replacement` string.
@ -248,76 +320,3 @@ select printf('%%%s %s %d', 'Hello', 'World', 2024);
│ %Hello World 2024 │
└──────────────────────────────────────────────┘
```
## overlay
Replace a part of a string `s` with another string `replace`, starting at 1-based index `offset`. By default, the number of bytes removed from `s` equals the length of `replace`. If `length` (the optional fourth argument) is specified, a different number of bytes is removed.
**Syntax**
```sql
overlay(s, replace, offset[, length])
```
**Parameters**
- `s`: A string type [String](../data-types/string.md).
- `replace`: A string type [String](../data-types/string.md).
- `offset`: An integer type [Int](../data-types/int-uint.md).
- `length`: Optional. An integer type [Int](../data-types/int-uint.md).
**Returned value**
- A [String](../data-types/string.md) data type value. If `offset` is negative the offset is counted starting from the back. `length` specifies the length of the snippet within input to be replaced.
**Example**
```sql
SELECT overlay('Spark SQL', 'CORE', 7) AS res;
```
Result:
```text
┌─res────────┐
│ Spark CORE │
└────────────┘
```
## overlayUTF8
Replace a part of a string `s` with another string `replace`, starting at 1-based index `offset`. By default, the number of characters removed from `s` equals the length of `replace`. If `length` (the optional fourth argument) is specified, a different number of characters is removed.
Assumes that the string contains valid UTF-8 encoded text. If this assumption is violated, no exception is thrown and the result is undefined.
**Syntax**
```sql
overlayUTF8(s, replace, offset[, length])
```
**Parameters**
- `s`: A string type [String](../data-types/string.md).
- `replace`: A string type [String](../data-types/string.md).
- `offset`: An integer type [Int](../data-types/int-uint.md).
- `length`: Optional. An integer type [Int](../data-types/int-uint.md).
**Returned value**
- A [String](../data-types/string.md) data type value. If `offset` is negative the offset is counted starting from the back. `length` specifies the length of the snippet within input to be replaced.
**Example**
```sql
SELECT overlayUTF8('ClickHouse是一款OLAP数据库', '开源', 12, 2) AS res;
```
Result:
```text
┌─res────────────────────────┐
│ ClickHouse是开源OLAP数据库 │
└────────────────────────────┘
```

8
src/Functions/overlay.cpp
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@ -201,14 +201,14 @@ private:
{
if (offset > 0)
{
if (static_cast<size_t>(offset) > input_size + 1) [[unlikely]]
if (static_cast<size_t>(offset) > input_size + 1)
return input_size;
else
return offset - 1;
}
else
{
if (input_size < -static_cast<size_t>(offset)) [[unlikely]]
if (input_size < -static_cast<size_t>(offset))
return 0;
else
return input_size + offset;
@ -704,14 +704,14 @@ REGISTER_FUNCTION(Overlay)
{
factory.registerFunction<FunctionOverlay<false>>(
{.description = R"(
Replace a part of a string `s` with another string `replace`, starting at 1-based index `offset`. By default, the number of bytes removed from `s` equals the length of `replace`. If `length` (the optional fourth argument) is specified, a different number of bytes is removed.
Replace a part of a string `input` with another string `replace`, starting at 1-based index `offset`. By default, the number of bytes removed from `input` equals the length of `replace`. If `length` (the optional fourth argument) is specified, a different number of bytes is removed.
)",
.categories{"String"}},
FunctionFactory::Case::Insensitive);
factory.registerFunction<FunctionOverlay<true>>(
{.description = R"(
Replace a part of a string `s` with another string `replace`, starting at 1-based index `offset`. By default, the number of bytes removed from `s` equals the length of `replace`. If `length` (the optional fourth argument) is specified, a different number of bytes is removed.
Replace a part of a string `input` with another string `replace`, starting at 1-based index `offset`. By default, the number of characters removed from `input` equals the length of `replace`. If `length` (the optional fourth argument) is specified, a different number of characters is removed.
Assumes that the string contains valid UTF-8 encoded text. If this assumption is violated, no exception is thrown and the result is undefined.
)",

2
tests/queries/0_stateless/02415_all_new_functions_must_be_documented.reference
View File

@ -512,8 +512,6 @@ nullIf
nullIn
nullInIgnoreSet
or
overlay
overlayUTF8
parseDateTime
parseDateTime32BestEffort
parseDateTime32BestEffortOrNull