-- -- UNION (also INTERSECT, EXCEPT) -- -- Simple UNION constructs SELECT 1 AS two UNION SELECT 2; SELECT 1 AS one UNION SELECT 1; SELECT 1 AS two UNION ALL SELECT 2; SELECT 1 AS two UNION ALL SELECT 1; SELECT 1 AS three UNION SELECT 2 UNION SELECT 3; SELECT 1 AS two UNION SELECT 2 UNION SELECT 2; SELECT 1 AS three UNION SELECT 2 UNION ALL SELECT 2; SELECT 1.1 AS two UNION SELECT 2.2; -- Mixed types SELECT 1.1 AS two UNION SELECT 2; SELECT 1 AS two UNION SELECT 2.2; SELECT 1 AS one UNION SELECT 1.0::float8; SELECT 1.1 AS two UNION ALL SELECT 2; SELECT 1.0::float8 AS two UNION ALL SELECT 1; SELECT 1.1 AS three UNION SELECT 2 UNION SELECT 3; SELECT 1.1::float8 AS two UNION SELECT 2 UNION SELECT 2.0::float8; SELECT 1.1 AS three UNION SELECT 2 UNION ALL SELECT 2; SELECT 1.1 AS two UNION (SELECT 2 UNION ALL SELECT 2); -- -- Try testing from tables... -- SELECT f1 AS five FROM FLOAT8_TBL UNION SELECT f1 FROM FLOAT8_TBL; SELECT f1 AS ten FROM FLOAT8_TBL UNION ALL SELECT f1 FROM FLOAT8_TBL; SELECT f1 AS nine FROM FLOAT8_TBL UNION SELECT f1 FROM INT4_TBL; SELECT f1 AS ten FROM FLOAT8_TBL UNION ALL SELECT f1 FROM INT4_TBL; SELECT f1 AS five FROM FLOAT8_TBL WHERE f1 BETWEEN -1e6 AND 1e6 UNION SELECT f1 FROM INT4_TBL WHERE f1 BETWEEN 0 AND 1000000; SELECT CAST(f1 AS char(4)) AS three FROM VARCHAR_TBL UNION SELECT f1 FROM CHAR_TBL; SELECT f1 AS three FROM VARCHAR_TBL UNION SELECT CAST(f1 AS varchar) FROM CHAR_TBL; SELECT f1 AS eight FROM VARCHAR_TBL UNION ALL SELECT f1 FROM CHAR_TBL; SELECT f1 AS five FROM TEXT_TBL UNION SELECT f1 FROM VARCHAR_TBL UNION SELECT TRIM(TRAILING FROM f1) FROM CHAR_TBL; -- -- INTERSECT and EXCEPT -- SELECT q2 FROM int8_tbl INTERSECT SELECT q1 FROM int8_tbl; SELECT q2 FROM int8_tbl INTERSECT ALL SELECT q1 FROM int8_tbl; SELECT q2 FROM int8_tbl EXCEPT SELECT q1 FROM int8_tbl; SELECT q2 FROM int8_tbl EXCEPT ALL SELECT q1 FROM int8_tbl; SELECT q2 FROM int8_tbl EXCEPT ALL SELECT DISTINCT q1 FROM int8_tbl; SELECT q1 FROM int8_tbl EXCEPT SELECT q2 FROM int8_tbl; SELECT q1 FROM int8_tbl EXCEPT ALL SELECT q2 FROM int8_tbl; SELECT q1 FROM int8_tbl EXCEPT ALL SELECT DISTINCT q2 FROM int8_tbl; -- -- Mixed types -- SELECT f1 FROM float8_tbl INTERSECT SELECT f1 FROM int4_tbl; SELECT f1 FROM float8_tbl EXCEPT SELECT f1 FROM int4_tbl; -- -- Operator precedence and (((((extra))))) parentheses -- SELECT q1 FROM int8_tbl INTERSECT SELECT q2 FROM int8_tbl UNION ALL SELECT q2 FROM int8_tbl; SELECT q1 FROM int8_tbl INTERSECT (((SELECT q2 FROM int8_tbl UNION ALL SELECT q2 FROM int8_tbl))); (((SELECT q1 FROM int8_tbl INTERSECT SELECT q2 FROM int8_tbl))) UNION ALL SELECT q2 FROM int8_tbl; SELECT q1 FROM int8_tbl UNION ALL SELECT q2 FROM int8_tbl EXCEPT SELECT q1 FROM int8_tbl; SELECT q1 FROM int8_tbl UNION ALL (((SELECT q2 FROM int8_tbl EXCEPT SELECT q1 FROM int8_tbl))); (((SELECT q1 FROM int8_tbl UNION ALL SELECT q2 FROM int8_tbl))) EXCEPT SELECT q1 FROM int8_tbl; -- -- Subqueries with ORDER BY & LIMIT clauses -- -- In this syntax, ORDER BY/LIMIT apply to the result of the EXCEPT SELECT q1,q2 FROM int8_tbl EXCEPT SELECT q2,q1 FROM int8_tbl ORDER BY q2,q1; -- This should fail, because q2 isn't a name of an EXCEPT output column SELECT q1 FROM int8_tbl EXCEPT SELECT q2 FROM int8_tbl ORDER BY q2 LIMIT 1; -- But this should work: SELECT q1 FROM int8_tbl EXCEPT (((SELECT q2 FROM int8_tbl ORDER BY q2 LIMIT 1))); -- -- New syntaxes (7.1) permit new tests -- (((((select * from int8_tbl)))));
