我在使用 CASE 语句更新 SQL 表时遇到问题。
SELECT number,amount,minimuminventory FROM artikel WHERE number=17;
+--------+--------+------------------+ | number | amount | minimuminventory | +--------+--------+------------------+ | 17 | 10 | 0 | +--------+--------+------------------+
I have an amount of 10 but when I update my table:
UPDATE artikel
SET amount = CASE WHEN amount - minimuminventory - 2 < 0
THEN amount=amount-2
ELSE amount=99
END
WHERE artnr=17;
Query OK, 1 rows affected (0,01 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql 更新我的表，集合数量为 0
SELECT number,amount,minimuminventory FROM artikel WHERE number=17;
+--------+--------+------------------+ | number | amount | minimuminventory | +--------+--------+------------------+ | 17 | 0 | 0 | +--------+--------+------------------+
你看到问题了吗？
最佳答案
amount = CASE WHEN amount - minimuminventory - 2 < 0 THEN amount=amount-2 ELSE amount=99 END
CASE 语句中的值是 amount 列的预期值，但您在它的 THEN 和 ELSE 部分中再次执行 amount=x。将其更改为:
amount = CASE WHEN amount - minimuminventory - 2 < 0 THEN amount-2 ELSE 99 END
关于MySQL Update CASE 用 "0"更新字段，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/22708639/