SELECT * FROM ((SELECT DISTINCT p.* FROM e_prodotti p WHERE p.preordine = 1 AND FIND_IN_SET(45,p.categoria) AND FIND_IN_SET(50,p.categoria)) UNION(SELECT DISTINCT p.* FROM e_prodotti p WHERE p.preordine = 1 AND FIND_IN_SET(45,p.categoria) AND FIND_IN_SET(51,p.categoria)) UNION(SELECT DISTINCT p.* FROM e_prodotti p WHERE p.preordine = 1 AND FIND_IN_SET(45,p.categoria) AND FIND_IN_SET(52,p.categoria)) UNION(SELECT DISTINCT p.* FROM e_prodotti p WHERE p.preordine = 1 AND FIND_IN_SET(45,p.categoria) AND FIND_IN_SET(55,p.categoria))) as tmp WHERE 1