union.sql

PostgreSQL7.4.6 for Linux

--
-- 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)))));