比如
score1, scroe2, score3
---------------------
-9 -5 9 select score1+scroe2+score3 结果是-5但是,我想让结果为负数的时候,抽取出来的数据为0,应该怎么做呢
score1, scroe2, score3
---------------------
-9 -5 9 select score1+scroe2+score3 结果是-5但是,我想让结果为负数的时候,抽取出来的数据为0,应该怎么做呢
mysql> create table e(score1 int not null,score2 int not null,score3 int not nul
l);
Query OK, 0 rows affected (0.03 sec)mysql> insert into e values(-9,-5,9);
Query OK, 1 row affected (0.03 sec)mysql> select * from e;
+--------+--------+--------+
| score1 | score2 | score3 |
+--------+--------+--------+
| -9 | -5 | 9 |
+--------+--------+--------+
1 row in set (0.02 sec)mysql> select (case when score1+score2+score3 < 0 then 0 else score1+score2+scor
e3 end) as score from e;
+-------+
| score |
+-------+
| 0 |
+-------+
1 row in set (0.00 sec)