Re-reading my latest MERGE patch, I realised there is a trivial,
pre-existing bug in the check for unreachable WHEN clauses, which
means it won't spot an unreachable WHEN clause if it doesn't have an
AND condition.
So the checks need to be re-ordered, as in the attached.
Regards,
Dean
diff --git a/src/backend/parser/parse_merge.c b/src/backend/parser/parse_merge.c
new file mode 100644
index 3844f2b..47d266b
--- a/src/backend/parser/parse_merge.c
+++ b/src/backend/parser/parse_merge.c
@@ -155,12 +155,12 @@ transformMergeStmt(ParseState *pstate, M
/*
* Check for unreachable WHEN clauses
*/
- if (mergeWhenClause->condition == NULL)
- is_terminal[when_type] = true;
- else if (is_terminal[when_type])
+ if (is_terminal[when_type])
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("unreachable WHEN clause specified after unconditional WHEN clause")));
+ if (mergeWhenClause->condition == NULL)
+ is_terminal[when_type] = true;
}
/*
diff --git a/src/test/regress/expected/merge.out b/src/test/regress/expected/merge.out
new file mode 100644
index 6c8a18f..bc53b21
--- a/src/test/regress/expected/merge.out
+++ b/src/test/regress/expected/merge.out
@@ -659,7 +659,7 @@ USING source AS s
ON t.tid = s.sid
WHEN MATCHED THEN /* Terminal WHEN clause for MATCHED */
DELETE
-WHEN MATCHED AND s.delta > 0 THEN
+WHEN MATCHED THEN
UPDATE SET balance = t.balance - s.delta;
ERROR: unreachable WHEN clause specified after unconditional WHEN clause
ROLLBACK;
diff --git a/src/test/regress/sql/merge.sql b/src/test/regress/sql/merge.sql
new file mode 100644
index 98fe104..fdbcd70
--- a/src/test/regress/sql/merge.sql
+++ b/src/test/regress/sql/merge.sql
@@ -438,7 +438,7 @@ USING source AS s
ON t.tid = s.sid
WHEN MATCHED THEN /* Terminal WHEN clause for MATCHED */
DELETE
-WHEN MATCHED AND s.delta > 0 THEN
+WHEN MATCHED THEN
UPDATE SET balance = t.balance - s.delta;
ROLLBACK;
