MySQL 'if exists' error

exists, mysql

Solution

Another method: You may also use `case when`

Select case
when exists(select * from tb_user where user_id=1)
then 'Ok'
else 'Not'
end
;

* SQLFiddle Demo

Sample table:

ID  NAME
1   john
2   tim
3   jack
4   rose

Query: renamed the columns as `Status`

Select case
when exists(select * from table1 where id=1)
then 'Ok'
else 'Not'
end as Status
;

Results:

STATUS
Ok

Problem

I got a error in my MySQL query: ``` if not exists(select * from tb_user where user_id=1) then select 'ok' as rul; else select 'not' as rul; end if; ``` Where's my problem?

Original source

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