MySQL更新案例更新字段为“0”

使用CASE语句更新SQL表时出现问题

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

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

你看到问题了吗

amount = CASE WHEN amount - minimuminventory - 2 < 0 THEN amount=amount-2 ELSE amount=99 END

你看到问题了吗

amount = CASE WHEN amount - minimuminventory - 2 < 0 THEN amount=amount-2 ELSE amount=99 END

在你的声明中：

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

这导致“金额”列中的值为0

更改更新语句，如下所示：

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

你看到问题了吗

amount = CASE WHEN amount - minimuminventory - 2 < 0 THEN amount=amount-2 ELSE amount=99 END

在你的声明中：

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

这导致“金额”列中的值为0

更改更新语句，如下所示：

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

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