Subqueries with ANY or SOME
语法描述
由于列子查询返回的结果集是多行一列,因此不能直接使用(=,>,<,>=,<=,<>)这些比较操作符。在列子查询中可以使用 ANY
、SOME
操作符与比较操作符联合使用:
ANY
:与比较操作符联合使用,表示与子查询返回的任何值比较为TRUE
,则返回结果为true
。SOME
:ANY
的别名,与ANY
意义相同,但较少使用。
语法结构
> SELECT column_name(s) FROM table_name WHERE column_name ANY (subquery);
示例
create table t1 (a int);
create table t2 (a int, b int);
create table t3 (a int);
create table t4 (a int not null, b int not null);
create table t5 (a int);
create table t6 (a int, b int);
insert into t1 values (2);
insert into t2 values (1,7),(2,7);
insert into t4 values (4,8),(3,8),(5,9);
insert into t5 values (null);
insert into t3 values (6),(7),(3);
insert into t6 values (10,7),(null,7);
mysql> select * from t3 where a <> any (select b from t2);
+------+
| a |
+------+
| 6 |
| 3 |
+------+
2 rows in set (0.00 sec)
mysql> select * from t3 where a <> some (select b from t2);
+------+
| a |
+------+
| 6 |
| 3 |
+------+
2 rows in set (0.00 sec)
mysql> select * from t3 where a = some (select b from t2);
+------+
| a |
+------+
| 7 |
+------+
1 row in set (0.00 sec)
mysql> select * from t3 where a = any (select b from t2);
+------+
| a |
+------+
| 7 |
+------+
1 row in set (0.00 sec)
mysql> select a,b from t6 where a > any ( select a ,b from t4 where a>3);
ERROR 1105 (HY000): subquery should return 1 column