MYSQL - INNER JOIN two tables result TRUE or FALSE-CodePudding

I have a below query that returns a result. How can query the result which if there is result, return True, and if there is no result, return FALSE??

SELECT a.id 
FROM table1 AS a 
INNER JOIN table2 AS c
   ON (a.id=c.user_id AND a.id=4 AND c.complete_date is NULL AND c.st_number= 8)

CodePudding user response：

You could use EXISTS here:

SELECT EXISTS (
    SELECT a.id
    FROM table1 AS a
    INNER JOIN table2 AS c ON a.id = c.user_id
    WHERE a.id = 4 AND c.complete_date IS NULL AND c.st_number = 8
);

CodePudding user response：

Try this,

Please don't merge inner join and where condition

SELECT a.id FROM table1 AS a 
INNER JOIN table2 AS c ON a.id=c.user_id 
where a.id=4 AND c.complete_date is NULL AND c.st_number= 8