小编use*_*606的帖子

我通过使用CASE语句更新我的SQL表有一个问题.

SELECT number,amount,minimuminventory FROM artikel WHERE number=17;

+--------+--------+------------------+
| number | amount | minimuminventory |
+--------+--------+------------------+
|     17 |     10 |                0 |
+--------+--------+------------------+

我的数量是10但是当我更新我的桌子时:

UPDATE artikel 
SET amount = CASE WHEN amount - minimuminventory - 2 < 0 
                  THEN amount=amount-2 
                  ELSE amount=99 
             END 
WHERE artnr=17;

查询正常,1行受影响(0,01秒)
匹配的行数:1已更改:1警告:0

mysql将我的表更新为0

SELECT number,amount,minimuminventory FROM artikel WHERE number=17;

+--------+--------+------------------+
| number | amount | minimuminventory |
+--------+--------+------------------+
|     17 |      0 |                0 |
+--------+--------+------------------+

你看到了问题吗？