MYSQL WHERE condition depends upon SELECT column

Is it possible to reference back to the column you're selecting in the WHERE condition?

I'm not even sure how to ask this question without excessive verbage, so I'll just try to point you to the "rated_user = @2User" part and note that @2User is what I'm selecting.

SELECT id, user, minimum 
 INTO @1ID, @1User, @minimum 
 FROM table1 
 WHERE a_or_b = 'a' AND item = itemName 
 ORDER BY number DESC LIMIT 1;
 
 SELECT id, user 
 INTO @2ID, @2User 
 FROM table1 
 WHERE a_or_b = 'b' AND item = itemName 
     AND (SELECT IFNULL(AVG(rating),0) AS Rating 
             FROM table2 
             WHERE rated_user = @2User AND completed = 'y'
         ) >= @minimum_seller_rating 
 ORDER BY number ASC LIMIT 1;
 

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