Mysql——查询字段是否为空

如何设置条件

  • isnull()

    select * from users where email = 'xxxx' and isnull(deletedAt)

  • is null

    select * from users where email = 'xxxx' and deletedAt is null

  • is not null

    select * from users where email = 'xxxx' and deletedAt is not null

  • !isnull()

    select * from users where email = 'xxxx' and !isnull(deletedAt) 

select * from users where email = 'xxxx' and not isnull(deletedAt)

  • isfull

  • 当查询条件为 null，用指定字符替代

    select name,  isfull(gender,'未知') as gender  from users where email = 'xxxx'
posted @ 2018-07-22 23:08  cnloop  阅读(34058)  评论(0)  编辑  收藏  举报