From eb145fdfea91ee5dc6d7aad0309527f810f7c90a Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Thu, 20 Jul 2017 11:29:36 -0400 Subject: [PATCH] Fix dumping of outer joins with empty qual lists. Normally, a JoinExpr would have empty "quals" only if it came from CROSS JOIN syntax. However, it's possible to get to this state by specifying NATURAL JOIN between two tables with no common column names, and there might be other ways too. The code previously printed no ON clause if "quals" was empty; that's right for CROSS JOIN but syntactically invalid if it's some type of outer join. Fix by printing ON TRUE in that case. This got broken by commit 2ffa740be, which stopped using NATURAL JOIN syntax in ruleutils output due to its brittleness in the face of column renamings. Back-patch to 9.3 where that commit appeared. Per report from Tushar Ahuja. Discussion: https://postgr.es/m/98b283cd-6dda-5d3f-f8ac-87db8c76a3da@enterprisedb.com --- src/backend/utils/adt/ruleutils.c | 5 ++++ src/test/regress/expected/create_view.out | 29 +++++++++++++++++++++++ src/test/regress/sql/create_view.sql | 10 ++++++++ 3 files changed, 44 insertions(+) diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c index d2fb20d5649..23000281bbe 100644 --- a/src/backend/utils/adt/ruleutils.c +++ b/src/backend/utils/adt/ruleutils.c @@ -10082,6 +10082,11 @@ get_from_clause_item(Node *jtnode, Query *query, deparse_context *context) if (!PRETTY_PAREN(context)) appendStringInfoChar(buf, ')'); } + else if (j->jointype != JOIN_INNER) + { + /* If we didn't say CROSS JOIN above, we must provide an ON */ + appendStringInfoString(buf, " ON TRUE"); + } if (!PRETTY_PAREN(context) || j->alias != NULL) appendStringInfoChar(buf, ')'); diff --git a/src/test/regress/expected/create_view.out b/src/test/regress/expected/create_view.out index 79f5dba55fc..c2da9add97e 100644 --- a/src/test/regress/expected/create_view.out +++ b/src/test/regress/expected/create_view.out @@ -1648,6 +1648,35 @@ select pg_get_viewdef('tt20v', true); CAST((1 + 2)::bigint AS bigint) i8(i8); (1 row) +-- corner cases with empty join conditions +create view tt21v as +select * from tt5 natural inner join tt6; +select pg_get_viewdef('tt21v', true); + pg_get_viewdef +---------------------- + SELECT tt5.a, + + tt5.b, + + tt5.cc, + + tt6.c, + + tt6.d + + FROM tt5 + + CROSS JOIN tt6; +(1 row) + +create view tt22v as +select * from tt5 natural left join tt6; +select pg_get_viewdef('tt22v', true); + pg_get_viewdef +----------------------------- + SELECT tt5.a, + + tt5.b, + + tt5.cc, + + tt6.c, + + tt6.d + + FROM tt5 + + LEFT JOIN tt6 ON TRUE; +(1 row) + -- clean up all the random objects we made above set client_min_messages = warning; DROP SCHEMA temp_view_test CASCADE; diff --git a/src/test/regress/sql/create_view.sql b/src/test/regress/sql/create_view.sql index 85c2959d3fd..6e7463cf14e 100644 --- a/src/test/regress/sql/create_view.sql +++ b/src/test/regress/sql/create_view.sql @@ -559,6 +559,16 @@ select * from cast(1+2 as int8) as i8; select pg_get_viewdef('tt20v', true); +-- corner cases with empty join conditions + +create view tt21v as +select * from tt5 natural inner join tt6; +select pg_get_viewdef('tt21v', true); + +create view tt22v as +select * from tt5 natural left join tt6; +select pg_get_viewdef('tt22v', true); + -- clean up all the random objects we made above set client_min_messages = warning; DROP SCHEMA temp_view_test CASCADE;