Mysql——查询字段是否为空
如何设置条件
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isnull()
select * from users where email = 'xxxx' and isnull(deletedAt)
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is null
select * from users where email = 'xxxx' and deletedAt is null
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is not null
select * from users where email = 'xxxx' and deletedAt is not null
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!isnull()
select * from users where email = 'xxxx' and !isnull(deletedAt) select * from users where email = 'xxxx' and not isnull(deletedAt)
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isfull
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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'