mysql的like模糊查询语句对于空值怎么处理?

Question

select * from ITEMINFO s where s.title like '%%' order by id desc 如果在%%之间不输入任何东西,好像会把全部数据都查询出来.怎么让它如果是空值,就提示 "没有找到数据"

Answer 1

既然都要查询空值或者null值，为何要模糊查询呢？这也不是多此一举了嘛。老铁

select * from ITEMINFO s where s.title = '' order by id desc

select * from ITEMINFO s where s.title is null order by id desc

Answer 2

先对数据过滤一道，如果是空值根本就不用查数据库。

Answer 3

这个需要在应用层做处理，数据库只存取数据,不做业务逻辑

Answer 4

select * from ITEMINFO s where s.title like '%%' and s.title <> '' order by id desc

Answer 5

select * from ITEMINFO s where s.title <> '' and s.title like '%%' order by id desc