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> ALTER NAMED COLLECTION 的文档

# ALTER NAMED COLLECTION

此查询用于修改已存在的命名集合。

<Note>
  部分 ClickHouse Cloud 服务支持启用通过 DDL 创建的命名集合。请联系 Support 确认可用性。
</Note>

**语法**

```sql theme={null}
ALTER NAMED COLLECTION [IF EXISTS] name [ON CLUSTER cluster]
[ SET
key_name1 = 'some value' [[NOT] OVERRIDABLE],
key_name2 = 'some value' [[NOT] OVERRIDABLE],
key_name3 = 'some value' [[NOT] OVERRIDABLE],
... ] |
[ DELETE key_name4, key_name5, ... ]
```

**示例**

```sql theme={null}
CREATE NAMED COLLECTION foobar AS a = '1' NOT OVERRIDABLE, b = '2';

ALTER NAMED COLLECTION foobar SET a = '2' OVERRIDABLE, c = '3';

ALTER NAMED COLLECTION foobar DELETE b;
```

**组成部分：** `ALTER`

**相关：** `CREATE NAMED COLLECTION`、`ALTER`、`DROP`