mysql - 是否可以仅将单元格值更新为特定的最大值？

Question

是否可以只将单元格值更新为特定的最大值？这是查询:

UPDATE table_1 SET premium_photos = premium_photos + 2 WHERE number = '1234'

我想将 premium_photos (tinyint) 值限制为最大值 4。这可能吗？例如，如果 premium_photos 当前值为 2 且查询为 + 3，则此查询后的值为 4。

Answer 1

尝试

UPDATE table_1 SET 
premium_photos = (CASE WHEN (premium_photos + 2) > 4 THEN 4 ELSE (premium_photos + 2) END) 
WHERE number = '1234'