使用 DELETE 语句删除数据。

    示例如下：

    假设有如下所示数据的表 t1 和 t2。其中，表 t2 为 KEY 分区表，且分区名由系统根据分区命令规则自动生成，即分区名为 p0、p1、p2、p3。

    1. obclient> CREATE TABLE t1(c1 int primary key, c2 int);
    2. Query OK, 0 rows affected (0.16 sec)
    3. obclient> INSERT t1 VALUES(1,1),(2,2),(3,3),(4,4);
    4. Query OK, 4 rows affected (0.00 sec)
    5. Records: 4  Duplicates: 0  Warnings: 0
    6. obclient> SELECT * FROM t1; 
    7. +----+------+
    8. | c1 | c2   |
    9. +----+------+
    10. |  1 |    1 |
    11. |  2 |    2 |
    12. |  3 |    3 |
    13. |  4 |    4 |
    14. +----+------+
    15. 4 rows in set (0.06 sec)
    17. obclient> CREATE TABLE t2(c1 int primary key, c2 int) partition BY key(c1) partitions 4;
    18. Query OK, 0 rows affected (0.19 sec)
    19. obclient> INSERT INTO t2 VALUES(5,5),(1,1),(2,2),(3,3);
    20. Query OK, 4 rows affected (0.01 sec)
    21. Records: 4  Duplicates: 0  Warnings: 0
    22. obclient> SELECT * FROM t2;
    23. +----+------+
    24. | c1 | c2   |
    25. +----+------+
    26. |  5 |    5 |
    27. |  1 |    1 |
    28. |  2 |    2 |
    29. |  3 |    3 |
    30. +----+------+
    31. 4 rows in set (0.02 sec)

    • 单表删除，删除 c1=2 的行，其中 c1 列为表 t1 中的 Primary Key。

      1. obclient> DELETE FROM t1 WHERE c1 = 2;
      2. Query OK, 1 row affected (0.02 sec)
      4. obclient> SELECT * FROM t1;
      5. +----+------+
      6. | c1 | c2   |
      7. +----+------+
      8. |  1 |    1 |
      9. |  3 |    3 |
      10. |  4 |    4 |
      11. +----+------+
      12. 3 rows in set (0.01 sec)

    • 单表删除，删除表 t1 中按照 c2 列排序之后的第一行数据。

      1. obclient> DELETE FROM t1 ORDER BY c2 LIMIT 1;
      2. Query OK, 1 row affected (0.01 sec)
      4. obclient> SELECT * FROM t1;
      5. +----+------+
      6. | c1 | c2   |
      7. +----+------+
      8. |  2 |    2 |
      9. |  3 |    3 |
      10. |  4 |    4 |
      11. +----+------+
      12. 3 rows in set (0.00 sec)

    • 单表删除，删除表 t2 的 p2 分区的数据。

      1. obclient> SELECT * FROM t2 PARTITION(p2); 
      2. +----+------+
      3. | c1 | c2   |
      4. +----+------+
      5. |  1 |    1 |
      6. |  2 |    2 |
      7. |  3 |    3 |
      8. +----+------+
      9. 3 rows in set (0.01 sec)
      11. obclient> DELETE FROM t2  PARTITION(p2); 
      12. Query OK, 3 rows affected (0.02 sec)
      14. obclient> SELECT * FROM t2;
      15. +----+------+
      16. | c1 | c2   | 
      17. +----+------+
      18. |  5 |    5 |
      19. +----+------+
      20. 1 row in set (0.02 sec)

    • 多表删除，删除 t1、t2 表中 t1.c1 = t2.c1 的数据。

      1. obclient> DELETE t1, t2 FROM t1, t2 WHERE t1.c1 = t2.c1;
      2. Query OK, 3 rows affected (0.02 sec)
      4. obclient> SELECT * FROM t1;
      5. +----+------+
      6. | c1 | c2   |
      7. +----+------+
      8. |  4 |    4 |
      9. +----+------+
      10. 1 row in set (0.01 sec)
      12. obclient> SELECT * FROM t2;
      13. +----+------+
      14. | c1 | c2   |
      15. +----+------+ 
      16. |  5 |    5 | 
      17. +----+------+
      18. 1 row in set (0.01 sec)

    • 多表删除，删除 t1、t2 表中 t1.c1 = t2.c1 的数据。

      1. obclient> DELETE FROM t1, t2 USING t1, t2 WHERE t1.c1 = t2.c1;
      2. Query OK, 4 rows affected (0.02 sec)
      4. obclient> SELECT * FROM t1;
      5. +----+------+
      6. | c1 | c2   |
      7. +----+------+
      8. |  4 |    4 |
      9. +----+------+
      10. 1 row in set (0.01 sec)
      12. obclient> SELECT * FROM t2;
      13. Empty set (0.01 sec)

    更多 DELETE 语句相关的语法说明请参见《SQL 参考（MySQL 模式）》中 DELETE 章节。