Question

I need help writing a query that will validate a first expression and than, if its true, will validate the following expression. Something like:

SELECT 
  name 
FROM 
  names 
WHERE 
  (tag_id = 1 OR tag_id = 2) AND (tag_id = 3 OR tag_id = 4)

Tried to use subqueries with if’s and exists, but no success.

Any help? Thanks,

Answer 1

Reading between the lines a bit, perhaps something like this:

SELECT n1.name
    FROM names n1
        INNER JOIN names n2
            ON n1.name = n2.name
    WHERE (n1.tag_id = 1 OR n1.tag_id = 2)
        AND (n2.tag_id = 3 OR n2.tag_id = 4)