要设置条件，请在MySQL中使用CASE WHEN语句。让我们首先创建一个表-mysql> create table DemoTable
-> (
-> Value1 int,
-> Value2 int,
-> Value3 int,
-> Value4 int
-> );
使用插入命令在表中插入一些记录-mysql> insert into DemoTable values(1,0,1,1);
mysql> insert into DemoTable values(1,0,1,0);
mysql> insert into DemoTable values(1,1,1,1);
mysql> insert into DemoTable values(0,0,0,0);
使用select语句显示表中的所有记录-mysql> select * from DemoTable;
这将产生以下输出-+--------+--------+--------+--------+
| Value1 | Value2 | Value3 | Value4 |
+--------+--------+--------+--------+
| 1 | 0 | 1 | 1 |
| 1 | 0 | 1 | 0 |
| 1 | 1 | 1 | 1 |
| 0 | 0 | 0 | 0 |
+--------+--------+--------+--------+
4 rows in set (0.00 sec)
这是在MySQL中设置值为0或1的列的条件的查询-mysql> select case when Value1+Value2+Value3+Value4
这将产生以下输出-+---------+
| Status |
+---------+
| Good |
| Good |
| Good |
| NotGood |
+---------+
4 rows in set (0.00 sec)