[SQL]交集Intersection

Q: Table1 和 Table2 的交集
SELECT t1.Chen FROM `sixtable` As t1, `sixtable` As t2 WHERE t1.Chen = t2.ChenSL1

Q: Table1, Table2和 Table3 的交集
SELECT t1.Chen FROM `sixtable` As t1, `sixtable` As t2 ,`sixtable` As t3 WHERE t1.Chen = t2.ChenSL1 and t1.Chen = t3.ChenSL2

以此類推...