Question

select * from prod where pic<>'' order by id desc 的问题

这个是读去 PIC不为空的 要读去PIC为空怎么写 谢谢个位

Answer 1

select * from prod where pic is not null order by id desc

数据库对空值的操作一般都是is null 和 is nor null

Answer 2

select * from prod where pic = '' or pic is null order by id desc

Answer 3

select * from prod where pic is null order by id desc