mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-09-21 01:00:48 +00:00
47 lines
1.3 KiB
Markdown
47 lines
1.3 KiB
Markdown
---
|
|
sidebar_position: 110
|
|
---
|
|
|
|
# groupArray {#agg_function-grouparray}
|
|
|
|
Syntax: `groupArray(x)` or `groupArray(max_size)(x)`
|
|
|
|
Creates an array of argument values.
|
|
Values can be added to the array in any (indeterminate) order.
|
|
|
|
The second version (with the `max_size` parameter) limits the size of the resulting array to `max_size` elements. For example, `groupArray(1)(x)` is equivalent to `[any (x)]`.
|
|
|
|
In some cases, you can still rely on the order of execution. This applies to cases when `SELECT` comes from a subquery that uses `ORDER BY`.
|
|
**Returned value**
|
|
|
|
|
|
**Example**
|
|
show default.ck table result.
|
|
|
|
``` text
|
|
┌─id─┬─name─────┐
|
|
│ 1 │ zhangsan │
|
|
│ 1 │ ᴺᵁᴸᴸ │
|
|
│ 1 │ lisi │
|
|
│ 2 │ wangwu │
|
|
└────┴──────────┘
|
|
|
|
```
|
|
|
|
Query:
|
|
|
|
``` sql
|
|
select id, groupArray(10)(name) from(select id,name from default.ck group by id,name order by id) group by id;
|
|
```
|
|
|
|
Result:
|
|
|
|
``` text
|
|
┌─id─┬─groupArray(10)(name)─┐
|
|
│ 1 │ ['zhangsan','lisi'] │
|
|
│ 2 │ ['wangwu'] │
|
|
└────┴──────────────────────┘
|
|
```
|
|
|
|
The groupArray function will remove Null value based on the above results .So,no matter that type is Nullable or non-null
|