---
{
    "title": "DELETE",
    "language": "zh-CN"
}
---

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# DELETE
## description

    该语句用于按条件删除指定 table（base index） partition 中的数据。
    该操作会同时删除和此 base index 相关的 rollup index 的数据。
    语法：
        DELETE FROM table_name [PARTITION partition_name | PARTITIONS (p1, p2)]
        WHERE
        column_name1 op { value | value_list } [ AND column_name2 op { value | value_list } ...];
        
    说明：
        1) op 的可选类型包括：=, >, <, >=, <=, !=, in, not in
        2) 只能指定 key 列上的条件。
        2) 当选定的 key 列不存在于某个 rollup 中时，无法进行 delete。
        3) 条件之间只能是“与”的关系。
           若希望达成“或”的关系，需要将条件分写在两个 DELETE 语句中。
        4) 如果为分区表，可以指定分区，如不指定，且会话变量 delete_without_partition 为 true，则会应用到所有分区。如果是单分区表，可以不指定。
           
    注意：
        该语句可能会降低执行后一段时间内的查询效率。
        影响程度取决于语句中指定的删除条件的数量。
        指定的条件越多，影响越大。

## example

    1. 删除 my_table partition p1 中 k1 列值为 3 的数据行
        DELETE FROM my_table PARTITION p1
        WHERE k1 = 3;
        
    2. 删除 my_table partition p1 中 k1 列值大于等于 3 且 k2 列值为 "abc" 的数据行
        DELETE FROM my_table PARTITION p1
        WHERE k1 >= 3 AND k2 = "abc";

    3. 删除 my_table partition p1, p2 中 k1 列值大于等于 3 且 k2 列值为 "abc" 的数据行
        DELETE FROM my_table PARTITIONS (p1, p2)
        WHERE k1 >= 3 AND k2 = "abc";
        
## keyword
    DELETE