Repair for bug #691 --- CREATE TABLE AS column aliases fail to be

applied when the select is a UNION (or other set-operation).

An alternative route to a fix would be to leave analyze.c alone and
change plan_set_operations in prepunion.c to take column names from
the topmost targetlist.  But I am not sure that would work in all
cases.  This patch seems the minimum-risk fix.

diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index e9cd224ad1d7cd82bbdf23eb6605d1434645ee71..287f986e8e172e853983cb217759ba34edf2b087 100644 (file)
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -2212,8 +2212,16 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
                qry->isBinary = FALSE;
        }
 
+       /*
+        * Any column names from CREATE TABLE AS need to be attached to both the
+        * top level and the leftmost subquery.  We do not do this earlier
+        * because we do *not* want the targetnames list to be affected.
+        */
        if (intoColNames)
+       {
                applyColumnNames(qry->targetList, intoColNames);
+               applyColumnNames(leftmostQuery->targetList, intoColNames);
+       }
 
        /*
         * As a first step towards supporting sort clauses that are