From a1e20e04d8f91f607a6c498989743f205dafa297 Mon Sep 17 00:00:00 2001 From: unknown Date: Mon, 29 Jan 2007 17:32:52 -0700 Subject: Bug#21904 (parser problem when using IN with a double "(())") Before this fix, a IN predicate of the form: "IN (( subselect ))", with two parenthesis, would be evaluated as a single row subselect: if the subselect returns more that 1 row, the statement would fail. The SQL:2003 standard defines a special exception in the specification, and mandates that this particular form of IN predicate shall be equivalent to "IN ( subselect )", which involves a table subquery and works with more than 1 row. This fix implements "IN (( subselect ))", "IN ((( subselect )))" etc as per the SQL:2003 requirement. All the details related to the implementation of this change have been commented in the code, and the relevant sections of the SQL:2003 spec are given for reference, so they are not repeated here. Having access to the spec is a requirement to review in depth this patch. mysql-test/r/subselect.result: Implement IN predicate special exceptions with subselects. mysql-test/t/subselect.test: Implement IN predicate special exceptions with subselects. sql/item_subselect.cc: Implement IN predicate special exceptions with subselects. sql/item_subselect.h: Implement IN predicate special exceptions with subselects. sql/sql_yacc.yy: Implement IN predicate special exceptions with subselects, cleanup. --- sql/item_subselect.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'sql/item_subselect.h') diff --git a/sql/item_subselect.h b/sql/item_subselect.h index f1be99353cc..c866cafd8c0 100644 --- a/sql/item_subselect.h +++ b/sql/item_subselect.h @@ -126,6 +126,12 @@ public: virtual void reset_value_registration() {} enum_parsing_place place() { return parsing_place; } + /** + Get the SELECT_LEX structure associated with this Item. + @return the SELECT_LEX structure associated with this Item + */ + st_select_lex* get_select_lex(); + friend class select_subselect; friend class Item_in_optimizer; friend bool Item_field::fix_fields(THD *, Item **); @@ -169,6 +175,16 @@ public: bool null_inside(); void bring_value(); + /** + This method is used to implement a special case of semantic tree + rewriting, mandated by a SQL:2003 exception in the specification. + The only caller of this method is handle_sql2003_note184_exception(), + see the code there for more details. + Do not call this method for other purposes. + @return the SELECT_LEX structure that was given in the constructor. + */ + st_select_lex* invalidate_and_restore_select_lex(); + friend class select_singlerow_subselect; }; -- cgit v1.2.1