diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/parser/analyze.c | 29 | ||||
| -rw-r--r-- | src/backend/parser/gram.y | 44 |
2 files changed, 52 insertions, 21 deletions
diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c index 28e192f51c8..65483892252 100644 --- a/src/backend/parser/analyze.c +++ b/src/backend/parser/analyze.c @@ -2466,7 +2466,7 @@ transformPLAssignStmt(ParseState *pstate, PLAssignStmt *stmt) /* * The rest mostly matches transformSelectStmt, except that we needn't - * consider WITH or DISTINCT, and we build a targetlist our own way. + * consider WITH or INTO, and we build a targetlist our own way. */ qry->commandType = CMD_SELECT; pstate->p_is_insert = false; @@ -2590,10 +2590,29 @@ transformPLAssignStmt(ParseState *pstate, PLAssignStmt *stmt) EXPR_KIND_GROUP_BY, false /* allow SQL92 rules */ ); - /* No DISTINCT clause */ - Assert(!sstmt->distinctClause); - qry->distinctClause = NIL; - qry->hasDistinctOn = false; + if (sstmt->distinctClause == NIL) + { + qry->distinctClause = NIL; + qry->hasDistinctOn = false; + } + else if (linitial(sstmt->distinctClause) == NULL) + { + /* We had SELECT DISTINCT */ + qry->distinctClause = transformDistinctClause(pstate, + &qry->targetList, + qry->sortClause, + false); + qry->hasDistinctOn = false; + } + else + { + /* We had SELECT DISTINCT ON */ + qry->distinctClause = transformDistinctOnClause(pstate, + sstmt->distinctClause, + &qry->targetList, + qry->sortClause); + qry->hasDistinctOn = true; + } /* transform LIMIT */ qry->limitOffset = transformLimitClause(pstate, sstmt->limitOffset, diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y index 31c95443a5b..7574d545e0e 100644 --- a/src/backend/parser/gram.y +++ b/src/backend/parser/gram.y @@ -389,7 +389,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query); OptTableElementList TableElementList OptInherit definition OptTypedTableElementList TypedTableElementList reloptions opt_reloptions - OptWith distinct_clause opt_definition func_args func_args_list + OptWith opt_definition func_args func_args_list func_args_with_defaults func_args_with_defaults_list aggr_args aggr_args_list func_as createfunc_opt_list alterfunc_opt_list @@ -401,6 +401,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query); name_list role_list from_clause from_list opt_array_bounds qualified_name_list any_name any_name_list type_name_list any_operator expr_list attrs + distinct_clause opt_distinct_clause target_list opt_target_list insert_column_list set_target_list set_clause_list set_clause def_list operator_def_list indirection opt_indirection @@ -11260,6 +11261,11 @@ select_clause: * As with select_no_parens, simple_select cannot have outer parentheses, * but can have parenthesized subclauses. * + * It might appear that we could fold the first two alternatives into one + * by using opt_distinct_clause. However, that causes a shift/reduce conflict + * against INSERT ... SELECT ... ON CONFLICT. We avoid the ambiguity by + * requiring SELECT DISTINCT [ON] to be followed by a non-empty target_list. + * * Note that sort clauses cannot be included at this level --- SQL requires * SELECT foo UNION SELECT bar ORDER BY baz * to be parsed as @@ -11497,8 +11503,13 @@ opt_all_clause: | /*EMPTY*/ ; +opt_distinct_clause: + distinct_clause { $$ = $1; } + | opt_all_clause { $$ = NIL; } + ; + opt_sort_clause: - sort_clause { $$ = $1;} + sort_clause { $$ = $1; } | /*EMPTY*/ { $$ = NIL; } ; @@ -15065,32 +15076,33 @@ role_list: RoleSpec * Therefore the returned struct is a SelectStmt. *****************************************************************************/ -PLpgSQL_Expr: opt_target_list +PLpgSQL_Expr: opt_distinct_clause opt_target_list from_clause where_clause group_clause having_clause window_clause opt_sort_clause opt_select_limit opt_for_locking_clause { SelectStmt *n = makeNode(SelectStmt); - n->targetList = $1; - n->fromClause = $2; - n->whereClause = $3; - n->groupClause = $4; - n->havingClause = $5; - n->windowClause = $6; - n->sortClause = $7; - if ($8) + n->distinctClause = $1; + n->targetList = $2; + n->fromClause = $3; + n->whereClause = $4; + n->groupClause = $5; + n->havingClause = $6; + n->windowClause = $7; + n->sortClause = $8; + if ($9) { - n->limitOffset = $8->limitOffset; - n->limitCount = $8->limitCount; + n->limitOffset = $9->limitOffset; + n->limitCount = $9->limitCount; if (!n->sortClause && - $8->limitOption == LIMIT_OPTION_WITH_TIES) + $9->limitOption == LIMIT_OPTION_WITH_TIES) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("WITH TIES cannot be specified without ORDER BY clause"))); - n->limitOption = $8->limitOption; + n->limitOption = $9->limitOption; } - n->lockingClause = $9; + n->lockingClause = $10; $$ = (Node *) n; } ; |