OceanBase DELETE
描述
该语句用来删除表中符合条件的行，包括单表删除及多表删除两种方式。
格式
Single-Table-Delete Syntax:
DELETE [hint_options] FROM tbl_name
[PARTITION (partition_name,...)]
[WHERE where_condition]
[ORDER BY order_expression_list]
[LIMIT row_count]
Multiple-Table-Delete Syntax:
DELETE [hint_options] tbl_name[.*] [, tbl_name[.*]] ...
FROM table_references
[WHERE where_condition]
Or:
DELETE [hint_options] FROM tbl_name[.*] [, tbl_name[.*]] ...
USING table_references
[WHERE where_condition]
where_condition:
expression
order_expression_list:
order_expression [, order_expression ...]
order_expression:
expression [ASC | DESC]
limit_row_count:
INT_VALUE
table_references:
{tbl_name | joined_table | table_subquery | select_with_parens} [, ...]
参数解释
|
参数 |
描述 |
|---|---|
|
hint_options |
指定 hint 选项。 |
|
tbl_name |
指定需要删除的表名。 |
|
partition_name |
需要删除表的对应分区名。 |
|
where_condition |
删除的表需要满足的过滤条件。 |
|
order_expression_list |
删除的表的排序键列表。 |
|
row_count |
删除的表的行数指定，指定的值只能为整数。 |
|
table_references |
多表删除时指定的待选择的表序列。 |
示例
示例表及数据基于以下定义：
obclient> create table t1(c1 int primary key, c2 int);
Query OK, 0 rows affected (0.16 sec)
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> 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 的按照 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：执行删除表 t2 的 p2 分区的数据。
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)
-
多表删除：删除 t2 表中的 p2 分区中和 t1 表中 "t1.c1 = t2.c1" 的数据。
obclient> DELETE t2 FROM t1,t2 PARTITION(p2) WHERE t1.c1 = t2.c1;
Query OK, 3 rows affected (0.02 sec)
obclient> select * from t2;
+----+------+
| c1 | c2 |
+----+------+
| 5 | 5 |
+----+------+
1 row in set (0.01 sec)-
对可更新视图 v 进行删除操作
obclient> create view v as select * from t1;
Query OK, 0 rows affected (0.07 sec)
obclient> delete from v where v.c1 = 1;
Query OK, 1 row affected (0.02 sec)
obclient> select * from v;
+----+------+
| c1 | c2 |
+----+------+
| 2 | 2 |
| 3 | 3 |
| 4 | 4 |
+----+------+
3 rows in set (0.01 sec)注意事项
不管是多表删除还是单表删除都不支持直接对子查询进行删除操作，比如：
delete from (select * from t1);