<
运算符说明
<
运算符用于比较运算。当 <
左边运算数值小于 <
右侧运算数值时,<
运算符返回结果为 true
。
语法结构
> SELECT x < y;
示例
mysql> SELECT 2 < 2;
+-------+
| 2 < 2 |
+-------+
| false |
+-------+
1 row in set (0.00 sec)
create table t1 (spID smallint,userID bigint,score int);
insert into t1 values (1,1,1);
insert into t1 values (2,2,2);
insert into t1 values (2,1,4);
insert into t1 values (3,3,3);
insert into t1 values (1,1,5);
insert into t1 values (4,6,10);
insert into t1 values (5,11,99);
mysql> select spID,userID,score from t1 where (userID-1)<spID;
+------+--------+-------+
| spid | userid | score |
+------+--------+-------+
| 1 | 1 | 1 |
| 2 | 2 | 2 |
| 2 | 1 | 4 |
| 3 | 3 | 3 |
| 1 | 1 | 5 |
+------+--------+-------+
5 rows in set (0.00 sec)
mysql> select spID,userID,score from t1 where spID<(userID-1);
+------+--------+-------+
| spid | userid | score |
+------+--------+-------+
| 4 | 6 | 10 |
| 5 | 11 | 99 |
+------+--------+-------+
2 rows in set (0.00 sec)