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
。
obclient> CREATE TABLE t1(c1 int primary key, c2 int);
Query OK, 0 rows affected (0.16 sec)
obclient> INSERT t1 VALUES(1,1),(2,2),(3,3),(4,4);
Query OK, 4 rows affected (0.00 sec)
Records: 4 Duplicates: 0 Warnings: 0
obclient> SELECT * FROM t1;
+----+------+
| c1 | c2 |
+----+------+
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 4 |
+----+------+
4 rows in set (0.06 sec)
obclient> CREATE TABLE t2(c1 int primary key, c2 int) partition BY key(c1) partitions 4;
Query OK, 0 rows affected (0.19 sec)
obclient> INSERT INTO t2 VALUES(5,5),(1,1),(2,2),(3,3);
Query OK, 4 rows affected (0.01 sec)
Records: 4 Duplicates: 0 Warnings: 0
obclient> SELECT * FROM t2;
+----+------+
| c1 | c2 |
+----+------+
| 5 | 5 |
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
+----+------+
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。obclient> DELETE FROM t1 WHERE c1 = 2;
Query OK, 1 row affected (0.02 sec)
obclient> SELECT * FROM t1;
+----+------+
| c1 | c2 |
+----+------+
| 1 | 1 |
| 3 | 3 |
| 4 | 4 |
+----+------+
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。obclient> DELETE FROM t1 ORDER BY c2 LIMIT 1;
Query OK, 1 row affected (0.01 sec)
obclient> SELECT * FROM t1;
+----+------+
| c1 | c2 |
+----+------+
| 2 | 2 |
| 3 | 3 |
| 4 | 4 |
+----+------+
3 rows in set (0.00 sec)
单表删除,删除表
t2
的p2
分区的数据。obclient> SELECT * FROM t2 PARTITION(p2);
+----+------+
| c1 | c2 |
+----+------+
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
+----+------+
3 rows in set (0.01 sec)
obclient> DELETE FROM t2 PARTITION(p2);
Query OK, 3 rows affected (0.02 sec)
obclient> SELECT * FROM t2;
+----+------+
| c1 | c2 |
+----+------+
| 5 | 5 |
+----+------+
1 row in set (0.02 sec)
多表删除,删除
t1
、t2
表中t1.c1 = t2.c1
的数据。obclient> DELETE t1, t2 FROM t1, t2 WHERE t1.c1 = t2.c1;
Query OK, 3 rows affected (0.02 sec)
obclient> SELECT * FROM t1;
+----+------+
| c1 | c2 |
+----+------+
| 4 | 4 |
+----+------+
1 row in set (0.01 sec)
obclient> SELECT * FROM t2;
+----+------+
| c1 | c2 |
+----+------+
| 5 | 5 |
+----+------+
1 row in set (0.01 sec)
多表删除,删除
t1
、t2
表中t1.c1 = t2.c1
的数据。obclient> DELETE FROM t1, t2 USING t1, t2 WHERE t1.c1 = t2.c1;
Query OK, 4 rows affected (0.02 sec)
obclient> SELECT * FROM t1;
+----+------+
| c1 | c2 |
+----+------+
| 4 | 4 |
+----+------+
1 row in set (0.01 sec)
obclient> SELECT * FROM t2;
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。