MySQL 更新情况

Question

如果另一列大于零，我需要更新一列。我写了这个

UPDATE `product` SET `quantity`= CASE
WHEN `price` > 0
THEN `quantity` = 1000
ELSE `quantity` = 0
END

问题是这个查询只影响了 47 行，而它应该是大约 1000 行。我做错了什么？

Answer 1

检查它应该影响多少行:

select count(1) from product where price>0 and quantity<>1000; select count(1) from product where price<>0 and quantity<>0;