mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-23 16:12:01 +00:00
115807e77a
* my changes to gitignore
* Corrections in English docs and Russian docs added.
* TOC corrections
* TOC fixed
* Revert "my changes to gitignore"
This reverts commit 5884b1e79b.
* Update docs/en/sql-reference/table-functions/null.md
* Update docs/en/sql-reference/table-functions/null.md
* Update docs/ru/sql-reference/table-functions/null.md
* Update docs/ru/sql-reference/table-functions/null.md
Co-authored-by: Olga Revyakina <revolg@yandex-team.ru>
Co-authored-by: BayoNet <da-daos@yandex.ru>
44 lines
1.1 KiB
Markdown
44 lines
1.1 KiB
Markdown
---
|
|
toc_priority: 53
|
|
toc_title: null function
|
|
---
|
|
|
|
# null {#null-function}
|
|
|
|
Creates a temporary table of the specified structure with the [Null](../../engines/table-engines/special/null.md) table engine. According to the `Null`-engine properties, the table data is ignored and the table itself is immediately droped right after the query execution. The function is used for the convenience of test writing and demonstrations.
|
|
|
|
**Syntax**
|
|
|
|
``` sql
|
|
null('structure')
|
|
```
|
|
|
|
**Parameter**
|
|
|
|
- `structure` — A list of columns and column types. [String](../../sql-reference/data-types/string.md).
|
|
|
|
**Returned value**
|
|
|
|
A temporary `Null`-engine table with the specified structure.
|
|
|
|
**Example**
|
|
|
|
Query with the `null` function:
|
|
|
|
``` sql
|
|
INSERT INTO function null('x UInt64') SELECT * FROM numbers_mt(1000000000);
|
|
```
|
|
can replace three queries:
|
|
|
|
```sql
|
|
CREATE TABLE t (x UInt64) ENGINE = Null;
|
|
INSERT INTO t SELECT * FROM numbers_mt(1000000000);
|
|
DROP TABLE IF EXISTS t;
|
|
```
|
|
|
|
See also:
|
|
|
|
- [Null table engine](../../engines/table-engines/special/null.md)
|
|
|
|
[Original article](https://clickhouse.tech/docs/en/sql-reference/table-functions/null/) <!--hide-->
|