-- -- JOIN -- Test JOIN clauses -- CREATE TABLE J1_TBL ( i integer, j integer, t text ); CREATE TABLE J2_TBL ( i integer, k integer ); INSERT INTO J1_TBL VALUES (1, 4, 'one'); INSERT INTO J1_TBL VALUES (2, 3, 'two'); INSERT INTO J1_TBL VALUES (3, 2, 'three'); INSERT INTO J1_TBL VALUES (4, 1, 'four'); INSERT INTO J1_TBL VALUES (5, 0, 'five'); INSERT INTO J1_TBL VALUES (6, 6, 'six'); INSERT INTO J1_TBL VALUES (7, 7, 'seven'); INSERT INTO J1_TBL VALUES (8, 8, 'eight'); INSERT INTO J1_TBL VALUES (0, NULL, 'zero'); INSERT INTO J1_TBL VALUES (NULL, NULL, 'null'); INSERT INTO J1_TBL VALUES (NULL, 0, 'zero'); 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); INSERT INTO J2_TBL VALUES (5, -5); INSERT INTO J2_TBL VALUES (5, -5); INSERT INTO J2_TBL VALUES (0, NULL); INSERT INTO J2_TBL VALUES (NULL, NULL); INSERT INTO J2_TBL VALUES (NULL, 0); -- -- 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); SELECT '' AS "xxx", * FROM J1_TBL CROSS JOIN J2_TBL a CROSS JOIN J2_TBL b; -- -- -- 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) ORDER BY a, d; SELECT '' AS "xxx", * FROM J1_TBL t1 (a, b, c) JOIN J2_TBL t2 (a, b) USING (b) ORDER BY b, t1.a; -- -- 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); -- 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); -- -- Non-equi-joins -- SELECT '' AS "xxx", * FROM J1_TBL JOIN J2_TBL ON (J1_TBL.i <= J2_TBL.k); -- -- Outer joins -- Note that OUTER is a noise word -- SELECT '' AS "xxx", * FROM J1_TBL LEFT OUTER JOIN J2_TBL USING (i) ORDER BY i; SELECT '' AS "xxx", * FROM J1_TBL LEFT JOIN J2_TBL USING (i) ORDER BY i; SELECT '' AS "xxx", * FROM J1_TBL RIGHT OUTER JOIN J2_TBL USING (i); SELECT '' AS "xxx", * FROM J1_TBL RIGHT JOIN J2_TBL USING (i); SELECT '' AS "xxx", * FROM J1_TBL FULL OUTER JOIN J2_TBL USING (i) ORDER BY i, t; SELECT '' AS "xxx", * FROM J1_TBL FULL JOIN J2_TBL USING (i) ORDER BY i, t; SELECT '' AS "xxx", * FROM J1_TBL LEFT JOIN J2_TBL USING (i) WHERE (k = 1); SELECT '' AS "xxx", * FROM J1_TBL LEFT JOIN J2_TBL USING (i) WHERE (i = 1); -- -- More complicated constructs -- -- UNION JOIN isn't implemented yet SELECT '' AS "xxx", * FROM J1_TBL UNION JOIN J2_TBL; -- -- Multiway full join -- CREATE TABLE t1 (name TEXT, n INTEGER); CREATE TABLE t2 (name TEXT, n INTEGER); CREATE TABLE t3 (name TEXT, n INTEGER); INSERT INTO t1 VALUES ( 'aa', 11 ); INSERT INTO t2 VALUES ( 'aa', 12 ); INSERT INTO t2 VALUES ( 'bb', 22 ); INSERT INTO t2 VALUES ( 'dd', 42 ); INSERT INTO t3 VALUES ( 'aa', 13 ); INSERT INTO t3 VALUES ( 'bb', 23 ); INSERT INTO t3 VALUES ( 'cc', 33 ); SELECT * FROM t1 FULL JOIN t2 USING (name) FULL JOIN t3 USING (name); -- -- Test interactions of join syntax and subqueries -- -- Basic cases (we expect planner to pull up the subquery here) SELECT * FROM (SELECT * FROM t2) as s2 INNER JOIN (SELECT * FROM t3) s3 USING (name); SELECT * FROM (SELECT * FROM t2) as s2 LEFT JOIN (SELECT * FROM t3) s3 USING (name); SELECT * FROM (SELECT * FROM t2) as s2 FULL JOIN (SELECT * FROM t3) s3 USING (name); -- Cases with non-nullable expressions in subquery results; -- make sure these go to null as expected SELECT * FROM (SELECT name, n as s2_n, 2 as s2_2 FROM t2) as s2 NATURAL INNER JOIN (SELECT name, n as s3_n, 3 as s3_2 FROM t3) s3; SELECT * FROM (SELECT name, n as s2_n, 2 as s2_2 FROM t2) as s2 NATURAL LEFT JOIN (SELECT name, n as s3_n, 3 as s3_2 FROM t3) s3; SELECT * FROM (SELECT name, n as s2_n, 2 as s2_2 FROM t2) as s2 NATURAL FULL JOIN (SELECT name, n as s3_n, 3 as s3_2 FROM t3) s3; SELECT * FROM (SELECT name, n as s1_n, 1 as s1_1 FROM t1) as s1 NATURAL INNER JOIN (SELECT name, n as s2_n, 2 as s2_2 FROM t2) as s2 NATURAL INNER JOIN (SELECT name, n as s3_n, 3 as s3_2 FROM t3) s3; SELECT * FROM (SELECT name, n as s1_n, 1 as s1_1 FROM t1) as s1 NATURAL FULL JOIN (SELECT name, n as s2_n, 2 as s2_2 FROM t2) as s2 NATURAL FULL JOIN (SELECT name, n as s3_n, 3 as s3_2 FROM t3) s3; SELECT * FROM (SELECT name, n as s1_n FROM t1) as s1 NATURAL FULL JOIN (SELECT * FROM (SELECT name, n as s2_n FROM t2) as s2 NATURAL FULL JOIN (SELECT name, n as s3_n FROM t3) as s3 ) ss2; SELECT * FROM (SELECT name, n as s1_n FROM t1) as s1 NATURAL FULL JOIN (SELECT * FROM (SELECT name, n as s2_n, 2 as s2_2 FROM t2) as s2 NATURAL FULL JOIN (SELECT name, n as s3_n FROM t3) as s3 ) ss2; -- Test for propagation of nullability constraints into sub-joins create temp table x (x1 int, x2 int); insert into x values (1,11); insert into x values (2,22); insert into x values (3,null); insert into x values (4,44); insert into x values (5,null); create temp table y (y1 int, y2 int); insert into y values (1,111); insert into y values (2,222); insert into y values (3,333); insert into y values (4,null); select * from x; select * from y; select * from x left join y on (x1 = y1 and x2 is not null); select * from x left join y on (x1 = y1 and y2 is not null); select * from (x left join y on (x1 = y1)) left join x xx(xx1,xx2) on (x1 = xx1); select * from (x left join y on (x1 = y1)) left join x xx(xx1,xx2) on (x1 = xx1 and x2 is not null); select * from (x left join y on (x1 = y1)) left join x xx(xx1,xx2) on (x1 = xx1 and y2 is not null); select * from (x left join y on (x1 = y1)) left join x xx(xx1,xx2) on (x1 = xx1 and xx2 is not null); -- these should NOT give the same answers as above select * from (x left join y on (x1 = y1)) left join x xx(xx1,xx2) on (x1 = xx1) where (x2 is not null); select * from (x left join y on (x1 = y1)) left join x xx(xx1,xx2) on (x1 = xx1) where (y2 is not null); select * from (x left join y on (x1 = y1)) left join x xx(xx1,xx2) on (x1 = xx1) where (xx2 is not null); -- -- Clean up -- DROP TABLE t1; DROP TABLE t2; DROP TABLE t3; DROP TABLE J1_TBL; DROP TABLE J2_TBL;