MySQL combine two queries

Question

I have two MySQL queries

QUERY:

SELECT sodnik_1 FROM prihodnji_krog  WHERE file_id=\'8778\' AND sodnik_1 != \'\'
UNION 
SELECT sodnik_2 FROM prihodnji_krog  WHE         


        

Answer 1

How about

SELECT * FROM
(
    SELECT sodnik_1 as value FROM prihodnji_krog  WHERE file_id='8778' AND sodnik_1 != ''
    UNION 
    SELECT sodnik_2 as value FROM prihodnji_krog  WHERE file_id='8778' AND sodnik_2 != ''
    UNION
    SELECT sodnik_3 as value FROM prihodnji_krog  WHERE file_id='8778' AND sodnik_3 != ''
    UNION
    SELECT sodnik_4 as value FROM prihodnji_krog  WHERE file_id='8778' AND sodnik_4 != ''
) x INNER JOIN 
(
    SELECT value FROM notification_sodniki WHERE user_id='16'
) y 
ON x.value = y.value

When you use subqueries in a FROM clause, it's like if you are making temporary tables. Then with the alias you can refer to them and do a INNER JOIN