MySQL in-operator must match all values?

Question

I\'ve made my own forum. When doing a search I want to find any threads where two (or more) specific users have participated. I came up with this:

SELECT * F         


        

Answer 1

SELECT * 
    FROM table1 
        INNER JOIN table2 
            ON table1.threadid=table2.threadid 
    WHERE table2.threadcontributor IN ('1','52512')
    GROUP BY table1.PrimaryKey
    HAVING COUNT(DISTINCT table2.threadcontributor) = 2