-- -- 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, k, t; SELECT '' AS "xxx", * FROM J1_TBL LEFT JOIN J2_TBL USING (i) ORDER BY i, k, t; 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, k, t; SELECT '' AS "xxx", * FROM J1_TBL FULL JOIN J2_TBL USING (i) ORDER BY i, k, 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 -- -- -- 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 ( 'bb', 11 ); INSERT INTO t2 VALUES ( 'bb', 12 ); INSERT INTO t2 VALUES ( 'cc', 22 ); INSERT INTO t2 VALUES ( 'ee', 42 ); INSERT INTO t3 VALUES ( 'bb', 13 ); INSERT INTO t3 VALUES ( 'cc', 23 ); INSERT INTO t3 VALUES ( 'dd', 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); -- -- regression test: check for bug with propagation of implied equality -- to outside an IN -- select count(*) from tenk1 a where unique1 in (select unique1 from tenk1 b join tenk1 c using (unique1) where b.unique2 = 42); -- -- regression test: check for failure to generate a plan with multiple -- degenerate IN clauses -- select count(*) from tenk1 x where x.unique1 in (select a.f1 from int4_tbl a,float8_tbl b where a.f1=b.f1) and x.unique1 = 0 and x.unique1 in (select aa.f1 from int4_tbl aa,float8_tbl bb where aa.f1=bb.f1); -- try that with GEQO too begin; set geqo = on; set geqo_threshold = 2; select count(*) from tenk1 x where x.unique1 in (select a.f1 from int4_tbl a,float8_tbl b where a.f1=b.f1) and x.unique1 = 0 and x.unique1 in (select aa.f1 from int4_tbl aa,float8_tbl bb where aa.f1=bb.f1); rollback; -- -- regression test: be sure we cope with proven-dummy append rels -- explain (costs off) select aa, bb, unique1, unique1 from tenk1 right join b on aa = unique1 where bb < bb and bb is null; select aa, bb, unique1, unique1 from tenk1 right join b on aa = unique1 where bb < bb and bb is null; -- -- regression test: check handling of empty-FROM subquery underneath outer join -- explain (costs off) select * from int8_tbl i1 left join (int8_tbl i2 join (select 123 as x) ss on i2.q1 = x) on i1.q2 = i2.q2 order by 1, 2; select * from int8_tbl i1 left join (int8_tbl i2 join (select 123 as x) ss on i2.q1 = x) on i1.q2 = i2.q2 order by 1, 2; -- -- regression test: check a case where join_clause_is_movable_into() gives -- an imprecise result -- analyze pg_enum; explain (costs off) select anname, outname, enumtypid from (select pa.proname as anname, coalesce(po.proname, typname) as outname from pg_type t left join pg_proc po on po.oid = t.typoutput join pg_proc pa on pa.oid = t.typanalyze) ss, pg_enum, pg_type t2 where anname = enumlabel and outname = t2.typname and enumtypid = t2.oid; select anname, outname, enumtypid from (select pa.proname as anname, coalesce(po.proname, typname) as outname from pg_type t left join pg_proc po on po.oid = t.typoutput join pg_proc pa on pa.oid = t.typanalyze) ss, pg_enum, pg_type t2 where anname = enumlabel and outname = t2.typname and enumtypid = t2.oid; -- -- Clean up -- DROP TABLE t1; DROP TABLE t2; DROP TABLE t3; DROP TABLE J1_TBL; DROP TABLE J2_TBL; -- Both DELETE and UPDATE allow the specification of additional tables -- to "join" against to determine which rows should be modified. CREATE TEMP TABLE t1 (a int, b int); CREATE TEMP TABLE t2 (a int, b int); CREATE TEMP TABLE t3 (x int, y int); INSERT INTO t1 VALUES (5, 10); INSERT INTO t1 VALUES (15, 20); INSERT INTO t1 VALUES (100, 100); INSERT INTO t1 VALUES (200, 1000); INSERT INTO t2 VALUES (200, 2000); INSERT INTO t3 VALUES (5, 20); INSERT INTO t3 VALUES (6, 7); INSERT INTO t3 VALUES (7, 8); INSERT INTO t3 VALUES (500, 100); DELETE FROM t3 USING t1 table1 WHERE t3.x = table1.a; SELECT * FROM t3; DELETE FROM t3 USING t1 JOIN t2 USING (a) WHERE t3.x > t1.a; SELECT * FROM t3; DELETE FROM t3 USING t3 t3_other WHERE t3.x = t3_other.x AND t3.y = t3_other.y; SELECT * FROM t3; -- Test join against inheritance tree create temp table t2a () inherits (t2); insert into t2a values (200, 2001); select * from t1 left join t2 on (t1.a = t2.a); -- Test matching of column name with wrong alias select t1.x from t1 join t3 on (t1.a = t3.x); -- -- regression test for 8.1 merge right join bug -- CREATE TEMP TABLE tt1 ( tt1_id int4, joincol int4 ); INSERT INTO tt1 VALUES (1, 11); INSERT INTO tt1 VALUES (2, NULL); CREATE TEMP TABLE tt2 ( tt2_id int4, joincol int4 ); INSERT INTO tt2 VALUES (21, 11); INSERT INTO tt2 VALUES (22, 11); set enable_hashjoin to off; set enable_nestloop to off; -- these should give the same results select tt1.*, tt2.* from tt1 left join tt2 on tt1.joincol = tt2.joincol; select tt1.*, tt2.* from tt2 right join tt1 on tt1.joincol = tt2.joincol; reset enable_hashjoin; reset enable_nestloop; -- -- regression test for 8.2 bug with improper re-ordering of left joins -- create temp table tt3(f1 int, f2 text); insert into tt3 select x, repeat('xyzzy', 100) from generate_series(1,10000) x; create index tt3i on tt3(f1); analyze tt3; create temp table tt4(f1 int); insert into tt4 values (0),(1),(9999); analyze tt4; SELECT a.f1 FROM tt4 a LEFT JOIN ( SELECT b.f1 FROM tt3 b LEFT JOIN tt3 c ON (b.f1 = c.f1) WHERE c.f1 IS NULL ) AS d ON (a.f1 = d.f1) WHERE d.f1 IS NULL; -- -- regression test for proper handling of outer joins within antijoins -- create temp table tt4x(c1 int, c2 int, c3 int); explain (costs off) select * from tt4x t1 where not exists ( select 1 from tt4x t2 left join tt4x t3 on t2.c3 = t3.c1 left join ( select t5.c1 as c1 from tt4x t4 left join tt4x t5 on t4.c2 = t5.c1 ) a1 on t3.c2 = a1.c1 where t1.c1 = t2.c2 ); -- -- regression test for problems of the sort depicted in bug #3494 -- create temp table tt5(f1 int, f2 int); create temp table tt6(f1 int, f2 int); insert into tt5 values(1, 10); insert into tt5 values(1, 11); insert into tt6 values(1, 9); insert into tt6 values(1, 2); insert into tt6 values(2, 9); select * from tt5,tt6 where tt5.f1 = tt6.f1 and tt5.f1 = tt5.f2 - tt6.f2; -- -- regression test for problems of the sort depicted in bug #3588 -- create temp table xx (pkxx int); create temp table yy (pkyy int, pkxx int); insert into xx values (1); insert into xx values (2); insert into xx values (3); insert into yy values (101, 1); insert into yy values (201, 2); insert into yy values (301, NULL); select yy.pkyy as yy_pkyy, yy.pkxx as yy_pkxx, yya.pkyy as yya_pkyy, xxa.pkxx as xxa_pkxx, xxb.pkxx as xxb_pkxx from yy left join (SELECT * FROM yy where pkyy = 101) as yya ON yy.pkyy = yya.pkyy left join xx xxa on yya.pkxx = xxa.pkxx left join xx xxb on coalesce (xxa.pkxx, 1) = xxb.pkxx; -- -- regression test for improper pushing of constants across outer-join clauses -- (as seen in early 8.2.x releases) -- create temp table zt1 (f1 int primary key); create temp table zt2 (f2 int primary key); create temp table zt3 (f3 int primary key); insert into zt1 values(53); insert into zt2 values(53); select * from zt2 left join zt3 on (f2 = f3) left join zt1 on (f3 = f1) where f2 = 53; create temp view zv1 as select *,'dummy'::text AS junk from zt1; select * from zt2 left join zt3 on (f2 = f3) left join zv1 on (f3 = f1) where f2 = 53; -- -- regression test for improper extraction of OR indexqual conditions -- (as seen in early 8.3.x releases) -- select a.unique2, a.ten, b.tenthous, b.unique2, b.hundred from tenk1 a left join tenk1 b on a.unique2 = b.tenthous where a.unique1 = 42 and ((b.unique2 is null and a.ten = 2) or b.hundred = 3); -- -- test proper positioning of one-time quals in EXISTS (8.4devel bug) -- prepare foo(bool) as select count(*) from tenk1 a left join tenk1 b on (a.unique2 = b.unique1 and exists (select 1 from tenk1 c where c.thousand = b.unique2 and $1)); execute foo(true); execute foo(false); -- -- test for sane behavior with noncanonical merge clauses, per bug #4926 -- begin; set enable_mergejoin = 1; set enable_hashjoin = 0; set enable_nestloop = 0; create temp table a (i integer); create temp table b (x integer, y integer); select * from a left join b on i = x and i = y and x = i; rollback; -- -- test NULL behavior of whole-row Vars, per bug #5025 -- select t1.q2, count(t2.*) from int8_tbl t1 left join int8_tbl t2 on (t1.q2 = t2.q1) group by t1.q2 order by 1; select t1.q2, count(t2.*) from int8_tbl t1 left join (select * from int8_tbl) t2 on (t1.q2 = t2.q1) group by t1.q2 order by 1; select t1.q2, count(t2.*) from int8_tbl t1 left join (select * from int8_tbl offset 0) t2 on (t1.q2 = t2.q1) group by t1.q2 order by 1; select t1.q2, count(t2.*) from int8_tbl t1 left join (select q1, case when q2=1 then 1 else q2 end as q2 from int8_tbl) t2 on (t1.q2 = t2.q1) group by t1.q2 order by 1; -- -- test incorrect failure to NULL pulled-up subexpressions -- begin; create temp table a ( code char not null, constraint a_pk primary key (code) ); create temp table b ( a char not null, num integer not null, constraint b_pk primary key (a, num) ); create temp table c ( name char not null, a char, constraint c_pk primary key (name) ); insert into a (code) values ('p'); insert into a (code) values ('q'); insert into b (a, num) values ('p', 1); insert into b (a, num) values ('p', 2); insert into c (name, a) values ('A', 'p'); insert into c (name, a) values ('B', 'q'); insert into c (name, a) values ('C', null); select c.name, ss.code, ss.b_cnt, ss.const from c left join (select a.code, coalesce(b_grp.cnt, 0) as b_cnt, -1 as const from a left join (select count(1) as cnt, b.a from b group by b.a) as b_grp on a.code = b_grp.a ) as ss on (c.a = ss.code) order by c.name; rollback; -- -- test incorrect handling of placeholders that only appear in targetlists, -- per bug #6154 -- SELECT * FROM ( SELECT 1 as key1 ) sub1 LEFT JOIN ( SELECT sub3.key3, sub4.value2, COALESCE(sub4.value2, 66) as value3 FROM ( SELECT 1 as key3 ) sub3 LEFT JOIN ( SELECT sub5.key5, COALESCE(sub6.value1, 1) as value2 FROM ( SELECT 1 as key5 ) sub5 LEFT JOIN ( SELECT 2 as key6, 42 as value1 ) sub6 ON sub5.key5 = sub6.key6 ) sub4 ON sub4.key5 = sub3.key3 ) sub2 ON sub1.key1 = sub2.key3; -- test the path using join aliases, too SELECT * FROM ( SELECT 1 as key1 ) sub1 LEFT JOIN ( SELECT sub3.key3, value2, COALESCE(value2, 66) as value3 FROM ( SELECT 1 as key3 ) sub3 LEFT JOIN ( SELECT sub5.key5, COALESCE(sub6.value1, 1) as value2 FROM ( SELECT 1 as key5 ) sub5 LEFT JOIN ( SELECT 2 as key6, 42 as value1 ) sub6 ON sub5.key5 = sub6.key6 ) sub4 ON sub4.key5 = sub3.key3 ) sub2 ON sub1.key1 = sub2.key3; -- -- test case where a PlaceHolderVar is used as a nestloop parameter -- EXPLAIN (COSTS OFF) SELECT qq, unique1 FROM ( SELECT COALESCE(q1, 0) AS qq FROM int8_tbl a ) AS ss1 FULL OUTER JOIN ( SELECT COALESCE(q2, -1) AS qq FROM int8_tbl b ) AS ss2 USING (qq) INNER JOIN tenk1 c ON qq = unique2; SELECT qq, unique1 FROM ( SELECT COALESCE(q1, 0) AS qq FROM int8_tbl a ) AS ss1 FULL OUTER JOIN ( SELECT COALESCE(q2, -1) AS qq FROM int8_tbl b ) AS ss2 USING (qq) INNER JOIN tenk1 c ON qq = unique2; -- -- nested nestloops can require nested PlaceHolderVars -- create temp table nt1 ( id int primary key, a1 boolean, a2 boolean ); create temp table nt2 ( id int primary key, nt1_id int, b1 boolean, b2 boolean, foreign key (nt1_id) references nt1(id) ); create temp table nt3 ( id int primary key, nt2_id int, c1 boolean, foreign key (nt2_id) references nt2(id) ); insert into nt1 values (1,true,true); insert into nt1 values (2,true,false); insert into nt1 values (3,false,false); insert into nt2 values (1,1,true,true); insert into nt2 values (2,2,true,false); insert into nt2 values (3,3,false,false); insert into nt3 values (1,1,true); insert into nt3 values (2,2,false); insert into nt3 values (3,3,true); explain (costs off) select nt3.id from nt3 as nt3 left join (select nt2.*, (nt2.b1 and ss1.a3) AS b3 from nt2 as nt2 left join (select nt1.*, (nt1.id is not null) as a3 from nt1) as ss1 on ss1.id = nt2.nt1_id ) as ss2 on ss2.id = nt3.nt2_id where nt3.id = 1 and ss2.b3; select nt3.id from nt3 as nt3 left join (select nt2.*, (nt2.b1 and ss1.a3) AS b3 from nt2 as nt2 left join (select nt1.*, (nt1.id is not null) as a3 from nt1) as ss1 on ss1.id = nt2.nt1_id ) as ss2 on ss2.id = nt3.nt2_id where nt3.id = 1 and ss2.b3; -- -- test case where a PlaceHolderVar is propagated into a subquery -- explain (costs off) select * from int8_tbl t1 left join (select q1 as x, 42 as y from int8_tbl t2) ss on t1.q2 = ss.x where 1 = (select 1 from int8_tbl t3 where ss.y is not null limit 1) order by 1,2; select * from int8_tbl t1 left join (select q1 as x, 42 as y from int8_tbl t2) ss on t1.q2 = ss.x where 1 = (select 1 from int8_tbl t3 where ss.y is not null limit 1) order by 1,2; -- -- test the corner cases FULL JOIN ON TRUE and FULL JOIN ON FALSE -- select * from int4_tbl a full join int4_tbl b on true; select * from int4_tbl a full join int4_tbl b on false; -- -- test for ability to use a cartesian join when necessary -- explain (costs off) select * from tenk1 join int4_tbl on f1 = twothousand, int4(sin(1)) q1, int4(sin(0)) q2 where q1 = thousand or q2 = thousand; explain (costs off) select * from tenk1 join int4_tbl on f1 = twothousand, int4(sin(1)) q1, int4(sin(0)) q2 where thousand = (q1 + q2); -- -- test ability to generate a suitable plan for a star-schema query -- explain (costs off) select * from tenk1, int8_tbl a, int8_tbl b where thousand = a.q1 and tenthous = b.q1 and a.q2 = 1 and b.q2 = 2; -- -- test a corner case in which we shouldn't apply the star-schema optimization -- explain (costs off) select t1.unique2, t1.stringu1, t2.unique1, t2.stringu2 from tenk1 t1 inner join int4_tbl i1 left join (select v1.x2, v2.y1, 11 AS d1 from (values(1,0)) v1(x1,x2) left join (values(3,1)) v2(y1,y2) on v1.x1 = v2.y2) subq1 on (i1.f1 = subq1.x2) on (t1.unique2 = subq1.d1) left join tenk1 t2 on (subq1.y1 = t2.unique1) where t1.unique2 < 42 and t1.stringu1 > t2.stringu2; select t1.unique2, t1.stringu1, t2.unique1, t2.stringu2 from tenk1 t1 inner join int4_tbl i1 left join (select v1.x2, v2.y1, 11 AS d1 from (values(1,0)) v1(x1,x2) left join (values(3,1)) v2(y1,y2) on v1.x1 = v2.y2) subq1 on (i1.f1 = subq1.x2) on (t1.unique2 = subq1.d1) left join tenk1 t2 on (subq1.y1 = t2.unique1) where t1.unique2 < 42 and t1.stringu1 > t2.stringu2; -- -- test extraction of restriction OR clauses from join OR clause -- (we used to only do this for indexable clauses) -- explain (costs off) select * from tenk1 a join tenk1 b on (a.unique1 = 1 and b.unique1 = 2) or (a.unique2 = 3 and b.hundred = 4); explain (costs off) select * from tenk1 a join tenk1 b on (a.unique1 = 1 and b.unique1 = 2) or (a.unique2 = 3 and b.ten = 4); explain (costs off) select * from tenk1 a join tenk1 b on (a.unique1 = 1 and b.unique1 = 2) or ((a.unique2 = 3 or a.unique2 = 7) and b.hundred = 4); -- -- test placement of movable quals in a parameterized join tree -- explain (costs off) select * from tenk1 t1 left join (tenk1 t2 join tenk1 t3 on t2.thousand = t3.unique2) on t1.hundred = t2.hundred and t1.ten = t3.ten where t1.unique1 = 1; explain (costs off) select * from tenk1 t1 left join (tenk1 t2 join tenk1 t3 on t2.thousand = t3.unique2) on t1.hundred = t2.hundred and t1.ten + t2.ten = t3.ten where t1.unique1 = 1; explain (costs off) select count(*) from tenk1 a join tenk1 b on a.unique1 = b.unique2 left join tenk1 c on a.unique2 = b.unique1 and c.thousand = a.thousand join int4_tbl on b.thousand = f1; select count(*) from tenk1 a join tenk1 b on a.unique1 = b.unique2 left join tenk1 c on a.unique2 = b.unique1 and c.thousand = a.thousand join int4_tbl on b.thousand = f1; explain (costs off) select b.unique1 from tenk1 a join tenk1 b on a.unique1 = b.unique2 left join tenk1 c on b.unique1 = 42 and c.thousand = a.thousand join int4_tbl i1 on b.thousand = f1 right join int4_tbl i2 on i2.f1 = b.tenthous order by 1; select b.unique1 from tenk1 a join tenk1 b on a.unique1 = b.unique2 left join tenk1 c on b.unique1 = 42 and c.thousand = a.thousand join int4_tbl i1 on b.thousand = f1 right join int4_tbl i2 on i2.f1 = b.tenthous order by 1; explain (costs off) select * from ( select unique1, q1, coalesce(unique1, -1) + q1 as fault from int8_tbl left join tenk1 on (q2 = unique2) ) ss where fault = 122 order by fault; select * from ( select unique1, q1, coalesce(unique1, -1) + q1 as fault from int8_tbl left join tenk1 on (q2 = unique2) ) ss where fault = 122 order by fault; -- -- test handling of potential equivalence clauses above outer joins -- explain (costs off) select q1, unique2, thousand, hundred from int8_tbl a left join tenk1 b on q1 = unique2 where coalesce(thousand,123) = q1 and q1 = coalesce(hundred,123); select q1, unique2, thousand, hundred from int8_tbl a left join tenk1 b on q1 = unique2 where coalesce(thousand,123) = q1 and q1 = coalesce(hundred,123); explain (costs off) select f1, unique2, case when unique2 is null then f1 else 0 end from int4_tbl a left join tenk1 b on f1 = unique2 where (case when unique2 is null then f1 else 0 end) = 0; select f1, unique2, case when unique2 is null then f1 else 0 end from int4_tbl a left join tenk1 b on f1 = unique2 where (case when unique2 is null then f1 else 0 end) = 0; -- -- another case with equivalence clauses above outer joins (bug #8591) -- explain (costs off) select a.unique1, b.unique1, c.unique1, coalesce(b.twothousand, a.twothousand) from tenk1 a left join tenk1 b on b.thousand = a.unique1 left join tenk1 c on c.unique2 = coalesce(b.twothousand, a.twothousand) where a.unique2 < 10 and coalesce(b.twothousand, a.twothousand) = 44; select a.unique1, b.unique1, c.unique1, coalesce(b.twothousand, a.twothousand) from tenk1 a left join tenk1 b on b.thousand = a.unique1 left join tenk1 c on c.unique2 = coalesce(b.twothousand, a.twothousand) where a.unique2 < 10 and coalesce(b.twothousand, a.twothousand) = 44; -- -- check handling of join aliases when flattening multiple levels of subquery -- explain (verbose, costs off) select foo1.join_key as foo1_id, foo3.join_key AS foo3_id, bug_field from (values (0),(1)) foo1(join_key) left join (select join_key, bug_field from (select ss1.join_key, ss1.bug_field from (select f1 as join_key, 666 as bug_field from int4_tbl i1) ss1 ) foo2 left join (select unique2 as join_key from tenk1 i2) ss2 using (join_key) ) foo3 using (join_key); select foo1.join_key as foo1_id, foo3.join_key AS foo3_id, bug_field from (values (0),(1)) foo1(join_key) left join (select join_key, bug_field from (select ss1.join_key, ss1.bug_field from (select f1 as join_key, 666 as bug_field from int4_tbl i1) ss1 ) foo2 left join (select unique2 as join_key from tenk1 i2) ss2 using (join_key) ) foo3 using (join_key); -- -- test successful handling of nested outer joins with degenerate join quals -- explain (verbose, costs off) select t1.* from text_tbl t1 left join (select *, '***'::text as d1 from int8_tbl i8b1) b1 left join int8_tbl i8 left join (select *, null::int as d2 from int8_tbl i8b2) b2 on (i8.q1 = b2.q1) on (b2.d2 = b1.q2) on (t1.f1 = b1.d1) left join int4_tbl i4 on (i8.q2 = i4.f1); select t1.* from text_tbl t1 left join (select *, '***'::text as d1 from int8_tbl i8b1) b1 left join int8_tbl i8 left join (select *, null::int as d2 from int8_tbl i8b2) b2 on (i8.q1 = b2.q1) on (b2.d2 = b1.q2) on (t1.f1 = b1.d1) left join int4_tbl i4 on (i8.q2 = i4.f1); explain (verbose, costs off) select t1.* from text_tbl t1 left join (select *, '***'::text as d1 from int8_tbl i8b1) b1 left join int8_tbl i8 left join (select *, null::int as d2 from int8_tbl i8b2, int4_tbl i4b2) b2 on (i8.q1 = b2.q1) on (b2.d2 = b1.q2) on (t1.f1 = b1.d1) left join int4_tbl i4 on (i8.q2 = i4.f1); select t1.* from text_tbl t1 left join (select *, '***'::text as d1 from int8_tbl i8b1) b1 left join int8_tbl i8 left join (select *, null::int as d2 from int8_tbl i8b2, int4_tbl i4b2) b2 on (i8.q1 = b2.q1) on (b2.d2 = b1.q2) on (t1.f1 = b1.d1) left join int4_tbl i4 on (i8.q2 = i4.f1); explain (verbose, costs off) select t1.* from text_tbl t1 left join (select *, '***'::text as d1 from int8_tbl i8b1) b1 left join int8_tbl i8 left join (select *, null::int as d2 from int8_tbl i8b2, int4_tbl i4b2 where q1 = f1) b2 on (i8.q1 = b2.q1) on (b2.d2 = b1.q2) on (t1.f1 = b1.d1) left join int4_tbl i4 on (i8.q2 = i4.f1); select t1.* from text_tbl t1 left join (select *, '***'::text as d1 from int8_tbl i8b1) b1 left join int8_tbl i8 left join (select *, null::int as d2 from int8_tbl i8b2, int4_tbl i4b2 where q1 = f1) b2 on (i8.q1 = b2.q1) on (b2.d2 = b1.q2) on (t1.f1 = b1.d1) left join int4_tbl i4 on (i8.q2 = i4.f1); -- -- test ability to push constants through outer join clauses -- explain (costs off) select * from int4_tbl a left join tenk1 b on f1 = unique2 where f1 = 0; explain (costs off) select * from tenk1 a full join tenk1 b using(unique2) where unique2 = 42; -- -- test that quals attached to an outer join have correct semantics, -- specifically that they don't re-use expressions computed below the join; -- we force a mergejoin so that coalesce(b.q1, 1) appears as a join input -- set enable_hashjoin to off; set enable_nestloop to off; explain (verbose, costs off) select a.q2, b.q1 from int8_tbl a left join int8_tbl b on a.q2 = coalesce(b.q1, 1) where coalesce(b.q1, 1) > 0; select a.q2, b.q1 from int8_tbl a left join int8_tbl b on a.q2 = coalesce(b.q1, 1) where coalesce(b.q1, 1) > 0; reset enable_hashjoin; reset enable_nestloop; -- -- test join removal -- begin; CREATE TEMP TABLE a (id int PRIMARY KEY, b_id int); CREATE TEMP TABLE b (id int PRIMARY KEY, c_id int); CREATE TEMP TABLE c (id int PRIMARY KEY); CREATE TEMP TABLE d (a int, b int); INSERT INTO a VALUES (0, 0), (1, NULL); INSERT INTO b VALUES (0, 0), (1, NULL); INSERT INTO c VALUES (0), (1); INSERT INTO d VALUES (1,3), (2,2), (3,1); -- all three cases should be optimizable into a simple seqscan explain (costs off) SELECT a.* FROM a LEFT JOIN b ON a.b_id = b.id; explain (costs off) SELECT b.* FROM b LEFT JOIN c ON b.c_id = c.id; explain (costs off) SELECT a.* FROM a LEFT JOIN (b left join c on b.c_id = c.id) ON (a.b_id = b.id); -- check optimization of outer join within another special join explain (costs off) select id from a where id in ( select b.id from b left join c on b.id = c.id ); -- check that join removal works for a left join when joining a subquery -- that is guaranteed to be unique by its GROUP BY clause explain (costs off) select d.* from d left join (select * from b group by b.id, b.c_id) s on d.a = s.id and d.b = s.c_id; -- similarly, but keying off a DISTINCT clause explain (costs off) select d.* from d left join (select distinct * from b) s on d.a = s.id and d.b = s.c_id; -- join removal is not possible when the GROUP BY contains a column that is -- not in the join condition explain (costs off) select d.* from d left join (select * from b group by b.id, b.c_id) s on d.a = s.id; -- similarly, but keying off a DISTINCT clause explain (costs off) select d.* from d left join (select distinct * from b) s on d.a = s.id; -- check join removal works when uniqueness of the join condition is enforced -- by a UNION explain (costs off) select d.* from d left join (select id from a union select id from b) s on d.a = s.id; -- check join removal with a cross-type comparison operator explain (costs off) select i8.* from int8_tbl i8 left join (select f1 from int4_tbl group by f1) i4 on i8.q1 = i4.f1; rollback; create temp table parent (k int primary key, pd int); create temp table child (k int unique, cd int); insert into parent values (1, 10), (2, 20), (3, 30); insert into child values (1, 100), (4, 400); -- this case is optimizable select p.* from parent p left join child c on (p.k = c.k); explain (costs off) select p.* from parent p left join child c on (p.k = c.k); -- this case is not select p.*, linked from parent p left join (select c.*, true as linked from child c) as ss on (p.k = ss.k); explain (costs off) select p.*, linked from parent p left join (select c.*, true as linked from child c) as ss on (p.k = ss.k); -- check for a 9.0rc1 bug: join removal breaks pseudoconstant qual handling select p.* from parent p left join child c on (p.k = c.k) where p.k = 1 and p.k = 2; explain (costs off) select p.* from parent p left join child c on (p.k = c.k) where p.k = 1 and p.k = 2; select p.* from (parent p left join child c on (p.k = c.k)) join parent x on p.k = x.k where p.k = 1 and p.k = 2; explain (costs off) select p.* from (parent p left join child c on (p.k = c.k)) join parent x on p.k = x.k where p.k = 1 and p.k = 2; -- bug 5255: this is not optimizable by join removal begin; CREATE TEMP TABLE a (id int PRIMARY KEY); CREATE TEMP TABLE b (id int PRIMARY KEY, a_id int); INSERT INTO a VALUES (0), (1); INSERT INTO b VALUES (0, 0), (1, NULL); SELECT * FROM b LEFT JOIN a ON (b.a_id = a.id) WHERE (a.id IS NULL OR a.id > 0); SELECT b.* FROM b LEFT JOIN a ON (b.a_id = a.id) WHERE (a.id IS NULL OR a.id > 0); rollback; -- another join removal bug: this is not optimizable, either begin; create temp table innertab (id int8 primary key, dat1 int8); insert into innertab values(123, 42); SELECT * FROM (SELECT 1 AS x) ss1 LEFT JOIN (SELECT q1, q2, COALESCE(dat1, q1) AS y FROM int8_tbl LEFT JOIN innertab ON q2 = id) ss2 ON true; rollback; -- another join removal bug: we must clean up correctly when removing a PHV begin; create temp table uniquetbl (f1 text unique); explain (costs off) select t1.* from uniquetbl as t1 left join (select *, '***'::text as d1 from uniquetbl) t2 on t1.f1 = t2.f1 left join uniquetbl t3 on t2.d1 = t3.f1; explain (costs off) select t0.* from text_tbl t0 left join (select case t1.ten when 0 then 'doh!'::text else null::text end as case1, t1.stringu2 from tenk1 t1 join int4_tbl i4 ON i4.f1 = t1.unique2 left join uniquetbl u1 ON u1.f1 = t1.string4) ss on t0.f1 = ss.case1 where ss.stringu2 !~* ss.case1; select t0.* from text_tbl t0 left join (select case t1.ten when 0 then 'doh!'::text else null::text end as case1, t1.stringu2 from tenk1 t1 join int4_tbl i4 ON i4.f1 = t1.unique2 left join uniquetbl u1 ON u1.f1 = t1.string4) ss on t0.f1 = ss.case1 where ss.stringu2 !~* ss.case1; rollback; -- bug #8444: we've historically allowed duplicate aliases within aliased JOINs select * from int8_tbl x join (int4_tbl x cross join int4_tbl y) j on q1 = f1; -- error select * from int8_tbl x join (int4_tbl x cross join int4_tbl y) j on q1 = y.f1; -- error select * from int8_tbl x join (int4_tbl x cross join int4_tbl y(ff)) j on q1 = f1; -- ok -- -- Test hints given on incorrect column references are useful -- select t1.uunique1 from tenk1 t1 join tenk2 t2 on t1.two = t2.two; -- error, prefer "t1" suggestipn select t2.uunique1 from tenk1 t1 join tenk2 t2 on t1.two = t2.two; -- error, prefer "t2" suggestion select uunique1 from tenk1 t1 join tenk2 t2 on t1.two = t2.two; -- error, suggest both at once -- -- Take care to reference the correct RTE -- select atts.relid::regclass, s.* from pg_stats s join pg_attribute a on s.attname = a.attname and s.tablename = a.attrelid::regclass::text join (select unnest(indkey) attnum, indexrelid from pg_index i) atts on atts.attnum = a.attnum where schemaname != 'pg_catalog'; -- -- Test LATERAL -- select unique2, x.* from tenk1 a, lateral (select * from int4_tbl b where f1 = a.unique1) x; explain (costs off) select unique2, x.* from tenk1 a, lateral (select * from int4_tbl b where f1 = a.unique1) x; select unique2, x.* from int4_tbl x, lateral (select unique2 from tenk1 where f1 = unique1) ss; explain (costs off) select unique2, x.* from int4_tbl x, lateral (select unique2 from tenk1 where f1 = unique1) ss; explain (costs off) select unique2, x.* from int4_tbl x cross join lateral (select unique2 from tenk1 where f1 = unique1) ss; select unique2, x.* from int4_tbl x left join lateral (select unique1, unique2 from tenk1 where f1 = unique1) ss on true; explain (costs off) select unique2, x.* from int4_tbl x left join lateral (select unique1, unique2 from tenk1 where f1 = unique1) ss on true; -- check scoping of lateral versus parent references -- the first of these should return int8_tbl.q2, the second int8_tbl.q1 select *, (select r from (select q1 as q2) x, (select q2 as r) y) from int8_tbl; select *, (select r from (select q1 as q2) x, lateral (select q2 as r) y) from int8_tbl; -- lateral with function in FROM select count(*) from tenk1 a, lateral generate_series(1,two) g; explain (costs off) select count(*) from tenk1 a, lateral generate_series(1,two) g; explain (costs off) select count(*) from tenk1 a cross join lateral generate_series(1,two) g; -- don't need the explicit LATERAL keyword for functions explain (costs off) select count(*) from tenk1 a, generate_series(1,two) g; -- lateral with UNION ALL subselect explain (costs off) select * from generate_series(100,200) g, lateral (select * from int8_tbl a where g = q1 union all select * from int8_tbl b where g = q2) ss; select * from generate_series(100,200) g, lateral (select * from int8_tbl a where g = q1 union all select * from int8_tbl b where g = q2) ss; -- lateral with VALUES explain (costs off) select count(*) from tenk1 a, tenk1 b join lateral (values(a.unique1)) ss(x) on b.unique2 = ss.x; select count(*) from tenk1 a, tenk1 b join lateral (values(a.unique1)) ss(x) on b.unique2 = ss.x; -- lateral with VALUES, no flattening possible explain (costs off) select count(*) from tenk1 a, tenk1 b join lateral (values(a.unique1),(-1)) ss(x) on b.unique2 = ss.x; select count(*) from tenk1 a, tenk1 b join lateral (values(a.unique1),(-1)) ss(x) on b.unique2 = ss.x; -- lateral injecting a strange outer join condition explain (costs off) select * from int8_tbl a, int8_tbl x left join lateral (select a.q1 from int4_tbl y) ss(z) on x.q2 = ss.z; select * from int8_tbl a, int8_tbl x left join lateral (select a.q1 from int4_tbl y) ss(z) on x.q2 = ss.z; -- lateral reference to a join alias variable select * from (select f1/2 as x from int4_tbl) ss1 join int4_tbl i4 on x = f1, lateral (select x) ss2(y); select * from (select f1 as x from int4_tbl) ss1 join int4_tbl i4 on x = f1, lateral (values(x)) ss2(y); select * from ((select f1/2 as x from int4_tbl) ss1 join int4_tbl i4 on x = f1) j, lateral (select x) ss2(y); -- lateral references requiring pullup select * from (values(1)) x(lb), lateral generate_series(lb,4) x4; select * from (select f1/1000000000 from int4_tbl) x(lb), lateral generate_series(lb,4) x4; select * from (values(1)) x(lb), lateral (values(lb)) y(lbcopy); select * from (values(1)) x(lb), lateral (select lb from int4_tbl) y(lbcopy); select * from int8_tbl x left join (select q1,coalesce(q2,0) q2 from int8_tbl) y on x.q2 = y.q1, lateral (values(x.q1,y.q1,y.q2)) v(xq1,yq1,yq2); select * from int8_tbl x left join (select q1,coalesce(q2,0) q2 from int8_tbl) y on x.q2 = y.q1, lateral (select x.q1,y.q1,y.q2) v(xq1,yq1,yq2); select x.* from int8_tbl x left join (select q1,coalesce(q2,0) q2 from int8_tbl) y on x.q2 = y.q1, lateral (select x.q1,y.q1,y.q2) v(xq1,yq1,yq2); select v.* from (int8_tbl x left join (select q1,coalesce(q2,0) q2 from int8_tbl) y on x.q2 = y.q1) left join int4_tbl z on z.f1 = x.q2, lateral (select x.q1,y.q1 union all select x.q2,y.q2) v(vx,vy); select v.* from (int8_tbl x left join (select q1,(select coalesce(q2,0)) q2 from int8_tbl) y on x.q2 = y.q1) left join int4_tbl z on z.f1 = x.q2, lateral (select x.q1,y.q1 union all select x.q2,y.q2) v(vx,vy); create temp table dual(); insert into dual default values; analyze dual; select v.* from (int8_tbl x left join (select q1,(select coalesce(q2,0)) q2 from int8_tbl) y on x.q2 = y.q1) left join int4_tbl z on z.f1 = x.q2, lateral (select x.q1,y.q1 from dual union all select x.q2,y.q2 from dual) v(vx,vy); explain (verbose, costs off) select * from int8_tbl a left join lateral (select *, a.q2 as x from int8_tbl b) ss on a.q2 = ss.q1; select * from int8_tbl a left join lateral (select *, a.q2 as x from int8_tbl b) ss on a.q2 = ss.q1; explain (verbose, costs off) select * from int8_tbl a left join lateral (select *, coalesce(a.q2, 42) as x from int8_tbl b) ss on a.q2 = ss.q1; select * from int8_tbl a left join lateral (select *, coalesce(a.q2, 42) as x from int8_tbl b) ss on a.q2 = ss.q1; -- lateral can result in join conditions appearing below their -- real semantic level explain (verbose, costs off) select * from int4_tbl i left join lateral (select * from int2_tbl j where i.f1 = j.f1) k on true; select * from int4_tbl i left join lateral (select * from int2_tbl j where i.f1 = j.f1) k on true; explain (verbose, costs off) select * from int4_tbl i left join lateral (select coalesce(i) from int2_tbl j where i.f1 = j.f1) k on true; select * from int4_tbl i left join lateral (select coalesce(i) from int2_tbl j where i.f1 = j.f1) k on true; explain (verbose, costs off) select * from int4_tbl a, lateral ( select * from int4_tbl b left join int8_tbl c on (b.f1 = q1 and a.f1 = q2) ) ss; select * from int4_tbl a, lateral ( select * from int4_tbl b left join int8_tbl c on (b.f1 = q1 and a.f1 = q2) ) ss; -- lateral reference in a PlaceHolderVar evaluated at join level explain (verbose, costs off) select * from int8_tbl a left join lateral (select b.q1 as bq1, c.q1 as cq1, least(a.q1,b.q1,c.q1) from int8_tbl b cross join int8_tbl c) ss on a.q2 = ss.bq1; select * from int8_tbl a left join lateral (select b.q1 as bq1, c.q1 as cq1, least(a.q1,b.q1,c.q1) from int8_tbl b cross join int8_tbl c) ss on a.q2 = ss.bq1; -- case requiring nested PlaceHolderVars explain (verbose, costs off) select * from int8_tbl c left join ( int8_tbl a left join (select q1, coalesce(q2,42) as x from int8_tbl b) ss1 on a.q2 = ss1.q1 cross join lateral (select q1, coalesce(ss1.x,q2) as y from int8_tbl d) ss2 ) on c.q2 = ss2.q1, lateral (select ss2.y offset 0) ss3; -- case that breaks the old ph_may_need optimization explain (verbose, costs off) select c.*,a.*,ss1.q1,ss2.q1,ss3.* from int8_tbl c left join ( int8_tbl a left join (select q1, coalesce(q2,f1) as x from int8_tbl b, int4_tbl b2 where q1 < f1) ss1 on a.q2 = ss1.q1 cross join lateral (select q1, coalesce(ss1.x,q2) as y from int8_tbl d) ss2 ) on c.q2 = ss2.q1, lateral (select * from int4_tbl i where ss2.y > f1) ss3; -- check processing of postponed quals (bug #9041) explain (verbose, costs off) select * from (select 1 as x offset 0) x cross join (select 2 as y offset 0) y left join lateral ( select * from (select 3 as z offset 0) z where z.z = x.x ) zz on zz.z = y.y; -- check we don't try to do a unique-ified semijoin with LATERAL explain (verbose, costs off) select * from (values (0,9998), (1,1000)) v(id,x), lateral (select f1 from int4_tbl where f1 = any (select unique1 from tenk1 where unique2 = v.x offset 0)) ss; select * from (values (0,9998), (1,1000)) v(id,x), lateral (select f1 from int4_tbl where f1 = any (select unique1 from tenk1 where unique2 = v.x offset 0)) ss; -- test some error cases where LATERAL should have been used but wasn't select f1,g from int4_tbl a, (select f1 as g) ss; select f1,g from int4_tbl a, (select a.f1 as g) ss; select f1,g from int4_tbl a cross join (select f1 as g) ss; select f1,g from int4_tbl a cross join (select a.f1 as g) ss; -- SQL:2008 says the left table is in scope but illegal to access here select f1,g from int4_tbl a right join lateral generate_series(0, a.f1) g on true; select f1,g from int4_tbl a full join lateral generate_series(0, a.f1) g on true; -- check we complain about ambiguous table references select * from int8_tbl x cross join (int4_tbl x cross join lateral (select x.f1) ss); -- LATERAL can be used to put an aggregate into the FROM clause of its query select 1 from tenk1 a, lateral (select max(a.unique1) from int4_tbl b) ss; -- check behavior of LATERAL in UPDATE/DELETE create temp table xx1 as select f1 as x1, -f1 as x2 from int4_tbl; -- error, can't do this: update xx1 set x2 = f1 from (select * from int4_tbl where f1 = x1) ss; update xx1 set x2 = f1 from (select * from int4_tbl where f1 = xx1.x1) ss; -- can't do it even with LATERAL: update xx1 set x2 = f1 from lateral (select * from int4_tbl where f1 = x1) ss; -- we might in future allow something like this, but for now it's an error: update xx1 set x2 = f1 from xx1, lateral (select * from int4_tbl where f1 = x1) ss; -- also errors: delete from xx1 using (select * from int4_tbl where f1 = x1) ss; delete from xx1 using (select * from int4_tbl where f1 = xx1.x1) ss; delete from xx1 using lateral (select * from int4_tbl where f1 = x1) ss;