是否可以仅将单元格值更新为特定的最大值？

Question

是否可以仅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.是否可能？例如，如果premium_photos当前值为2且查询为+ 3，则此查询值后将为4.

Answer 1

试

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

Answer 2

您也可以使用IF功能

UPDATE table_1 SET
   premium_photos = IF(premium_photos+2>4, 4, premium_photos+2)
WHERE number = '1234'

IF() function documentation