postgres/src/test/regress/sql/join.sql

--
-- JOIN
-- Test join clauses
--

CREATE TABLE J1_TBL (
  i integer,
  j integer,
  t text
);

CREATE TABLE J2_TBL (
  i integer,
  k integer
);

CREATE TABLE JOIN3_TBL (
  i integer,
  j integer,
  y integer
);

CREATE TABLE JOIN4_TBL (
  k integer,
  z integer
);

INSERT INTO J1_TBL VALUES (1, 3, 'one');
INSERT INTO J1_TBL VALUES (2, 2, 'two');
INSERT INTO J1_TBL VALUES (3, 1, 'three');
INSERT INTO J1_TBL VALUES (4, 0, 'four');

INSERT INTO J2_TBL VALUES (1, -1);
INSERT INTO J2_TBL VALUES (2, 2);
INSERT INTO J2_TBL VALUES (3, -3);
INSERT INTO J2_TBL VALUES (2, 4);

--
-- CORRELATION NAMES
-- Make sure that table/column aliases are supported
-- before diving into more complex join syntax.
--

SELECT '' AS "xxx", *
  FROM J1_TBL AS tx;

SELECT '' AS "xxx", *
  FROM J1_TBL tx;

SELECT '' AS "xxx", *
  FROM J1_TBL AS t1 (a, b, c);

SELECT '' AS "xxx", *
  FROM J1_TBL t1 (a, b, c);

SELECT '' AS "xxx", *
  FROM J1_TBL t1 (a, b, c), J2_TBL t2 (d, e);

SELECT '' AS "xxx", t1.a, t2.e
  FROM J1_TBL t1 (a, b, c), J2_TBL t2 (d, e)
  WHERE t1.a = t2.d;


--
-- CROSS JOIN
-- Qualifications are not allowed on cross joins,
-- which degenerate into a standard unqualified inner join.
--

SELECT '' AS "xxx", *
  FROM J1_TBL CROSS JOIN J2_TBL;

-- ambiguous column
SELECT '' AS "xxx", i, k, t
  FROM J1_TBL CROSS JOIN J2_TBL;

-- resolve previous ambiguity by specifying the table name
SELECT '' AS "xxx", t1.i, k, t
  FROM J1_TBL t1 CROSS JOIN J2_TBL t2;

SELECT '' AS "xxx", ii, tt, kk
  FROM (J1_TBL CROSS JOIN J2_TBL)
    AS tx (ii, jj, tt, ii2, kk);

SELECT '' AS "xxx", tx.ii, tx.jj, tx.kk
  FROM (J1_TBL t1 (a, b, c) CROSS JOIN J2_TBL t2 (d, e))
    AS tx (ii, jj, tt, ii2, kk);


--
--
-- Inner joins (equi-joins)
--
--

--
-- Inner joins (equi-joins) with USING clause
-- The USING syntax changes the shape of the resulting table
-- by including a column in the USING clause only once in the result.
--

-- Inner equi-join on specified column
SELECT '' AS "xxx", *
  FROM J1_TBL INNER JOIN J2_TBL USING (i);

-- Same as above, slightly different syntax
SELECT '' AS "xxx", *
  FROM J1_TBL JOIN J2_TBL USING (i);

SELECT '' AS "xxx", *
  FROM J1_TBL t1 (a, b, c) JOIN J2_TBL t2 (a, d) USING (a);

SELECT '' AS "xxx", *
  FROM J1_TBL t1 (a, b, c) JOIN J2_TBL t2 (a, b) USING (b);


--
-- NATURAL JOIN
-- Inner equi-join on all columns with the same name
--

SELECT '' AS "xxx", *
  FROM J1_TBL NATURAL JOIN J2_TBL;

SELECT '' AS "xxx", *
  FROM J1_TBL t1 (a, b, c) NATURAL JOIN J2_TBL t2 (a, d);

SELECT '' AS "xxx", *
  FROM J1_TBL t1 (a, b, c) NATURAL JOIN J2_TBL t2 (d, a);

SELECT '' AS "xxx", *
  FROM J1_TBL t1 (a, b, c) NATURAL JOIN J2_TBL t2 (d, a);

-- mismatch number of columns
-- currently, Postgres will fill in with underlying names
SELECT '' AS "xxx", *
  FROM J1_TBL t1 (a, b) NATURAL JOIN J2_TBL t2 (a);


--
-- Inner joins (equi-joins)
--

SELECT '' AS "xxx", *
  FROM J1_TBL JOIN J2_TBL ON (J1_TBL.i = J2_TBL.i);

SELECT '' AS "xxx", *
  FROM J1_TBL JOIN J2_TBL ON (J1_TBL.i = J2_TBL.k);

SELECT '' AS "xxx", *
  FROM J1_TBL CROSS JOIN J2_TBL;


--
-- Non-equi-joins
--

SELECT '' AS "xxx", *
  FROM J1_TBL JOIN J2_TBL ON (J1_TBL.i <= J2_TBL.k);


--
-- Outer joins
--

SELECT '' AS "xxx", *
  FROM J1_TBL OUTER JOIN J2_TBL USING (i);

SELECT '' AS "xxx", *
  FROM J1_TBL LEFT OUTER JOIN J2_TBL USING (i);

SELECT '' AS "xxx", *
  FROM J1_TBL RIGHT OUTER JOIN J2_TBL USING (i);

SELECT '' AS "xxx", *
  FROM J1_TBL FULL OUTER JOIN J2_TBL USING (i);


--
-- More complicated constructs
--

--
-- Clean up
--

DROP TABLE J1_TBL;
DROP TABLE J2_TBL;