SELECT a.col_1,a.col_2,b.col_3,b.col_1,b.col_4 FROM ( SELECT col_1,col_2 FROM Table_A ) a LEFT JOIN( SELECT col_3,col_1,col_4 FROM Table_b ) b ON a.col_1=b.col_1 UNION ALL SELECT a.col_1,a.col_2,b.col_3,b.col_1,b.col_4 FROM ( SELECT col_1,col_2 FROM Table_B ) b LEFT JOIN( SELECT col_1,col_2 FROM Table_A ) a ON a.col_1=b.col_1 WHERE a.col_1 IS NULL