diff options
Diffstat (limited to 'src/backend')
| -rw-r--r-- | src/backend/parser/analyze.c | 13 | ||||
| -rw-r--r-- | src/backend/parser/gram.y | 8 | ||||
| -rw-r--r-- | src/backend/parser/parse_clause.c | 19 |
3 files changed, 38 insertions, 2 deletions
diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c index a9d1fecff5c..60cce378453 100644 --- a/src/backend/parser/analyze.c +++ b/src/backend/parser/analyze.c @@ -2018,6 +2018,19 @@ transformReturningList(ParseState *pstate, List *returningList) /* transform RETURNING identically to a SELECT targetlist */ rlist = transformTargetList(pstate, returningList, EXPR_KIND_RETURNING); + /* + * Complain if the nonempty tlist expanded to nothing (which is possible + * if it contains only a star-expansion of a zero-column table). If we + * allow this, the parsed Query will look like it didn't have RETURNING, + * with results that would probably surprise the user. + */ + if (rlist == NIL) + ereport(ERROR, + (errcode(ERRCODE_SYNTAX_ERROR), + errmsg("RETURNING must have at least one column"), + parser_errposition(pstate, + exprLocation(linitial(returningList))))); + /* mark column origins */ markTargetListOrigins(pstate, rlist); diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y index 8fced4427b1..f9d45777ca7 100644 --- a/src/backend/parser/gram.y +++ b/src/backend/parser/gram.y @@ -334,7 +334,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query); name_list from_clause from_list opt_array_bounds qualified_name_list any_name any_name_list any_operator expr_list attrs - target_list insert_column_list set_target_list + target_list opt_target_list insert_column_list set_target_list set_clause_list set_clause multiple_set_clause ctext_expr_list ctext_row def_list indirection opt_indirection reloption_list group_clause TriggerFuncArgs select_limit @@ -9259,7 +9259,7 @@ select_clause: * However, this is not checked by the grammar; parse analysis must check it. */ simple_select: - SELECT opt_distinct target_list + SELECT opt_distinct opt_target_list into_clause from_clause where_clause group_clause having_clause window_clause { @@ -12215,6 +12215,10 @@ ctext_row: '(' ctext_expr_list ')' { $$ = $2; } * *****************************************************************************/ +opt_target_list: target_list { $$ = $1; } + | /* EMPTY */ { $$ = NIL; } + ; + target_list: target_el { $$ = list_make1($1); } | target_list ',' target_el { $$ = lappend($1, $3); } diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c index 939fa834e0a..87b0c8fd418 100644 --- a/src/backend/parser/parse_clause.c +++ b/src/backend/parser/parse_clause.c @@ -2011,6 +2011,20 @@ transformDistinctClause(ParseState *pstate, true); } + /* + * Complain if we found nothing to make DISTINCT. Returning an empty list + * would cause the parsed Query to look like it didn't have DISTINCT, with + * results that would probably surprise the user. Note: this case is + * presently impossible for aggregates because of grammar restrictions, + * but we check anyway. + */ + if (result == NIL) + ereport(ERROR, + (errcode(ERRCODE_SYNTAX_ERROR), + is_agg ? + errmsg("an aggregate with DISTINCT must have at least one argument") : + errmsg("SELECT DISTINCT must have at least one column"))); + return result; } @@ -2115,6 +2129,11 @@ transformDistinctOnClause(ParseState *pstate, List *distinctlist, true); } + /* + * An empty result list is impossible here because of grammar restrictions. + */ + Assert(result != NIL); + return result; } |