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92 lines
3.4 KiB
Markdown
92 lines
3.4 KiB
Markdown
---
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toc_priority: 112
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---
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# groupArrayInsertAt {#grouparrayinsertat}
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Inserts a value into the array at the specified position.
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**Syntax**
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``` sql
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groupArrayInsertAt(default_x, size)(x, pos)
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```
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If in one query several values are inserted into the same position, the function behaves in the following ways:
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- If a query is executed in a single thread, the first one of the inserted values is used.
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- If a query is executed in multiple threads, the resulting value is an undetermined one of the inserted values.
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**Arguments**
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- `x` — Value to be inserted. [Expression](../../../sql-reference/syntax.md#syntax-expressions) resulting in one of the [supported data types](../../../sql-reference/data-types/index.md).
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- `pos` — Position at which the specified element `x` is to be inserted. Index numbering in the array starts from zero. [UInt32](../../../sql-reference/data-types/int-uint.md#uint-ranges).
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- `default_x` — Default value for substituting in empty positions. Optional parameter. [Expression](../../../sql-reference/syntax.md#syntax-expressions) resulting in the data type configured for the `x` parameter. If `default_x` is not defined, the [default values](../../../sql-reference/statements/create/table.md#create-default-values) are used.
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- `size` — Length of the resulting array. Optional parameter. When using this parameter, the default value `default_x` must be specified. [UInt32](../../../sql-reference/data-types/int-uint.md#uint-ranges).
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**Returned value**
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- Array with inserted values.
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Type: [Array](../../../sql-reference/data-types/array.md#data-type-array).
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**Example**
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Query:
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``` sql
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SELECT groupArrayInsertAt(toString(number), number * 2) FROM numbers(5);
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```
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Result:
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``` text
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┌─groupArrayInsertAt(toString(number), multiply(number, 2))─┐
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│ ['0','','1','','2','','3','','4'] │
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└───────────────────────────────────────────────────────────┘
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```
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Query:
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``` sql
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SELECT groupArrayInsertAt('-')(toString(number), number * 2) FROM numbers(5);
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```
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Result:
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``` text
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┌─groupArrayInsertAt('-')(toString(number), multiply(number, 2))─┐
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│ ['0','-','1','-','2','-','3','-','4'] │
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└────────────────────────────────────────────────────────────────┘
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```
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Query:
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``` sql
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SELECT groupArrayInsertAt('-', 5)(toString(number), number * 2) FROM numbers(5);
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```
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Result:
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``` text
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┌─groupArrayInsertAt('-', 5)(toString(number), multiply(number, 2))─┐
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│ ['0','-','1','-','2'] │
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└───────────────────────────────────────────────────────────────────┘
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```
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Multi-threaded insertion of elements into one position.
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Query:
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``` sql
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SELECT groupArrayInsertAt(number, 0) FROM numbers_mt(10) SETTINGS max_block_size = 1;
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```
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As a result of this query you get random integer in the `[0,9]` range. For example:
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``` text
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┌─groupArrayInsertAt(number, 0)─┐
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│ [7] │
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└───────────────────────────────┘
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```
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