mysql 符号查询 mysql字段空值在前端怎么检验 – 数据库 – 前端 linux mysql 查看库

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

is nullselect * from users where email = xxxx and deletedAt is null

is not nullselect * 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