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Update partition.md

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Внес поправки в английскую версию.
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Dmitriy 2020-11-30 23:33:30 +03:00
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docs/en/sql-reference/statements/alter/partition.md
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@ -233,6 +233,46 @@ ALTER TABLE hits MOVE PART '20190301_14343_16206_438' TO VOLUME 'slow'
ALTER TABLE hits MOVE PARTITION '2019-09-01' TO DISK 'fast_ssd'
```
## UPDATE IN PARTITION {#update-in-partition}
Allows to manipulate data in the specifies partition matching the specified filtering expression. Implemented as a [mutation](../../../sql-reference/statements/alter/index.md#mutations).
Syntax:
``` sql
ALTER TABLE [db.]table UPDATE column1 = expr1 [, ...] [IN PARTITION partition_id] WHERE filter_expr
```
### Example
``` sql
ALTER TABLE mt UPDATE x = x + 1 IN PARTITION 2 WHERE p = 2;
```
### See Also
- [UPDATE](../../../sql-reference/statements/alter/update.md#alter-table-update-statements)
## DELETE IN PARTITION {#delete-in-partition}
Allows to delete data in the specifies partition matching the specified filtering expression. Implemented as a [mutation](../../../sql-reference/statements/alter/index.md#mutations).
Syntax:
``` sql
ALTER TABLE [db.]table DELETE [IN PARTITION partition_id] WHERE filter_expr
```
### Example
``` sql
ALTER TABLE mt DELETE IN PARTITION 2 WHERE p = 2;
```
### See Also
- [DELETE](../../../sql-reference/statements/alter/delete.md#alter-mutations)
## How to Set Partition Expression {#alter-how-to-specify-part-expr}
You can specify the partition expression in `ALTER ... PARTITION` queries in different ways:
@ -250,28 +290,6 @@ All the rules above are also true for the [OPTIMIZE](../../../sql-reference/stat
OPTIMIZE TABLE table_not_partitioned PARTITION tuple() FINAL;
```
## UPDATE\|DELETE IN PARTITION {#update-delete-in-partition}
``` sql
ALTER TABLE table_name UPDATE update_expr [IN PARTITION partition_id] WHERE where_expr
```
``` sql
ALTER TABLE table_name DELETE [IN PARTITION partition_id] WHERE where_expr
```
`IN PARTITION` specifies the partition to which the [UPDATE](../../../sql-reference/statements/alter/update.md#alter-table-update-statements) or [DELETE](../../../sql-reference/statements/alter/delete.md#alter-mutations) expressions will be applied as a result of the query `ALTER TABLE`. New parts will be created only from the specified partition.
In this way, `IN PARTITION` helps reduce the load when the table is divided into many partitions, and you only need to update the data point-by-point.
Examples:
``` sql
ALTER TABLE mt UPDATE x = x + 1 IN PARTITION 2 WHERE p = 2;
```
``` sql
ALTER TABLE mt DELETE IN PARTITION 2 WHERE p = 2;
```
`IN PARTITION` specifies the partition to which the [UPDATE](../../../sql-reference/statements/alter/update.md#alter-table-update-statements) or [DELETE](../../../sql-reference/statements/alter/delete.md#alter-mutations) expressions will be applied as a result of the query `ALTER TABLE`. New parts will be created only from the specified partition. In this way, `IN PARTITION` helps reduce the load when the table is divided into many partitions, and you only need to update the data point-by-point.
The examples of `ALTER ... PARTITION` queries are demonstrated in the tests [`00502_custom_partitioning_local`](https://github.com/ClickHouse/ClickHouse/blob/master/tests/queries/0_stateless/00502_custom_partitioning_local.sql) and [`00502_custom_partitioning_replicated_zookeeper`](https://github.com/ClickHouse/ClickHouse/blob/master/tests/queries/0_stateless/00502_custom_partitioning_replicated_zookeeper.sql).