Implementation of WL#2486 -

"Process NATURAL and USING joins according to SQL:2003".

* Some of the main problems fixed by the patch:
  - in "select *" queries the * expanded correctly according to
    ANSI for arbitrary natural/using joins
  - natural/using joins are correctly transformed into JOIN ... ON
    for any number/nesting of the joins.
  - column references are correctly resolved against natural joins
    of any nesting and combined with arbitrary other joins.

* This patch also contains a fix for name resolution of items
  inside the ON condition of JOIN ... ON - in this case items must
  be resolved only against the JOIN operands. To support such
  'local' name resolution, the patch introduces a stack of
  name resolution contexts used at parse time.

NOTICE:
- This patch is not complete in the sense that
  - there are 2 test cases that still do not pass -
    one in join.test, one in select.test. Both are marked
    with a comment "TODO: WL#2486".
  - it does not include a new test specific for the task


mysql-test/include/ps_query.inc:
  Adjusted according to standard NATURAL/USING join semantics.,
mysql-test/r/bdb.result:
  Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/derived.result:
  Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/errors.result:
  The column as a whole cannot be resolved, so different error message.
mysql-test/r/fulltext.result:
  Adjusted according to standard JOIN ... ON semantics =>
  the ON condition can refer only to the join operands.
mysql-test/r/fulltext_order_by.result:
  More detailed error message.
mysql-test/r/innodb.result:
  Adjusted according to standard NATURAL/USING join semantics.
  This test doesn't pass completetly yet!
mysql-test/r/insert_select.result:
  More detailed error message.
mysql-test/r/join.result:
  Adjusted according to standard NATURAL/USING join semantics.
  
  NOTICE: there is one test case that still fails, and it is
  commeted out and marked with WL#2486 in the test file.
mysql-test/r/join_crash.result:
  Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/join_nested.result:
  Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/join_outer.result:
  Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/multi_update.result:
  Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/null_key.result:
  Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/order_by.result:
  Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/ps_2myisam.result:
  Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/ps_3innodb.result:
  Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/ps_4heap.result:
  Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/ps_5merge.result:
  Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/ps_6bdb.result:
  Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/ps_7ndb.result:
  Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/select.result:
  Adjusted according to standard NATURAL/USING join semantics.
  
  NOTICE: there is one failing test case which is commented with
  WL#2486 in the test file.
mysql-test/r/subselect.result:
  Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/type_ranges.result:
  Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/union.result:
  More detailed error message.
mysql-test/t/bdb.test:
  Adjusted according to standard NATURAL/USING join semantics.
mysql-test/t/errors.test:
  Adjusted according to standard NATURAL/USING join semantics.
mysql-test/t/fulltext.test:
  Adjusted according to standard JOIN ... ON semantics =>
  the ON condition can refer only to the join operands.
mysql-test/t/fulltext_order_by.test:
  More detailed error message.
mysql-test/t/innodb.test:
  Adjusted according to standard NATURAL/USING join semantics.
  This test doesn't pass completetly yet!
mysql-test/t/insert_select.test:
  More detailed error message.
mysql-test/t/join.test:
  Adjusted according to standard NATURAL/USING join semantics.
  
  NOTICE: there is one test case that still fails, and it is
  commeted out and marked with WL#2486 in the test file.
mysql-test/t/join_crash.test:
  Adjusted according to standard NATURAL/USING join semantics.
mysql-test/t/join_nested.test:
  Adjusted according to standard NATURAL/USING join semantics.
mysql-test/t/join_outer.test:
  Adjusted according to standard NATURAL/USING join semantics.
mysql-test/t/null_key.test:
  Adjusted according to standard NATURAL/USING join semantics.
mysql-test/t/order_by.test:
  Adjusted according to standard NATURAL/USING join semantics.
mysql-test/t/select.test:
  Adjusted according to standard NATURAL/USING join semantics.
  
  NOTICE: there is one test case that still fails, and it is
  commeted out and marked with WL#2486 in the test file.
mysql-test/t/subselect.test:
  Adjusted according to standard NATURAL/USING join semantics.
mysql-test/t/type_ranges.test:
  Adjusted according to standard NATURAL/USING join semantics.
mysql-test/t/union.test:
  More detailed error message.
sql/item.cc:
  - extra parameter to find_field_in_tables
  - find_field_in_real_table renamed to find_field_in_table
  - fixed comments/typos
sql/item.h:
  - added [first | last]_name_resolution_table to class
    Name_resolution_context
  - commented old code
  - standardized formatting
sql/mysql_priv.h:
  - refactored the find_field_in_XXX procedures,
  - added a new procedure for natural join table references,
  - renamed the find_field_in_XXX procedures to clearer names
sql/sp.cc:
  - pass the top-most list of the FROM clause to setup_tables
  - extra parameter to find_field_in_tables
sql/sql_acl.cc:
  - renamed find_field_in_table => find_field_in_table_ref
  - extra parameter to find_field_in_table_ref
  - commented old code
sql/sql_base.cc:
  This file contains the core of the implementation of the processing
  of NATURAL/USING joins (WL#2486).
  - added many comments to old code
  - refactored the group of find_field_in_XXX procedures, and added a
    new procedure for natural joins. There is one find_field_in_XXX procedure
    per each type of table reference (stored table, merge view, or natural
    join); one meta-procedure that selects the correct one depeneding on the
    table reference; and one procedure that goes over a list of table
    referenes.
  - NATURAL/USING joins are processed through the procedures:
      mark_common_columns, store_natural_using_join_columns,
      store_top_level_join_columns, setup_natural_join_row_types.
    The entry point to processing NATURAL/USING joins is the
    procedure 'setup_natural_join_row_types'.
  - Replaced the specialized Field_iterator_XXX iterators with one
    generic iterator over the fields of a table reference.
  - Simplified 'insert_fields' and 'setup_conds' due to encapsulation of
    the processing of natural joins in a separate set of procedures.
sql/sql_class.h:
  - Commented old code.
sql/sql_delete.cc:
  - Pass the FROM clause to setup_tables.
sql/sql_help.cc:
  - pass the end name resolution table to find_field_in_tables
  - adjust the list of tables for name resolution
sql/sql_insert.cc:
  - Changed the code that saves and restores the current context to
    support the list of tables for name resolution -
    context->first_name_resolution_table, and
    table_list->next_name_resolution_table.
    Needed to support an ugly trick to resolve inserted columns only in
    the first table.
  - Added Name_resolution_context::[first | last]_name_resolution_table.
  - Commented old code
sql/sql_lex.cc:
  - set select_lex.parent_lex correctly
  - set correct state of the current name resolution context
sql/sql_lex.h:
  - Added a stack of name resolution contexts to support local
    contexts for JOIN ... ON conditions.
  - Commented old code.
sql/sql_load.cc:
  - Pass the FROM clause to setup_tables.
sql/sql_olap.cc:
  - Pass the FROM clause to setup_tables.
sql/sql_parse.cc:
  - correctly set SELECT_LEX::parent_lex
  - set the first table of the current name resoltion context
  - added support for NATURAL/USING joins
  - commented old code
sql/sql_select.cc:
  - Pass the FROM clause to setup_tables.
  - Pass the end table to find_field_in_tables
  - Improved comments
sql/sql_show.cc:
  - Set SELECT_LEX::parent_lex.
sql/sql_update.cc:
  - Pass the FROM clause to setup_tables.
sql/sql_yacc.yy:
  - Added support for a stack of name resolution contexts needed to
    implement name resolution for JOIN ... ON. A context is pushed
    for each new JOIN ... ON, and popped afterwards.
  - Added support for NATURAL/USING joins.
sql/table.cc:
  - Added new class Natural_join_column to hide the heterogeneous
    representation of column references for stored tables and for
    views.
  - Added a new list TABLE_LIST::next_name_resolution_table to
    support name resolution with NATURAL/USING joins. Also added
    other members to TABLE_LIST to support NATURAL/USING joins.
  - Added a generic iterator over the fields of table references
    of various types - class Field_iterator_table_ref
sql/table.h:
  - Added new class Natural_join_column to hide the heterogeneous
    representation of column references for stored tables and for
    views.
  - Added a new list TABLE_LIST::next_name_resolution_table to
    support name resolution with NATURAL/USING joins. Also added
    other members to TABLE_LIST to support NATURAL/USING joins.
  - Added a generic iterator over the fields of table references
    of various types - class Field_iterator_table_ref
tests/mysql_client_test.c:
  Adjusted according to standard NATURAL JOIN syntax.

1 files changed, 41 insertions, 5 deletions

diff --git a/sql/sql_lex.h b/sql/sql_lex.h
index 4bba0c432c7..51d765889ba 100644
--- a/sql/sql_lex.h
+++ b/sql/sql_lex.h
@@ -471,14 +471,16 @@ class st_select_lex: public st_select_lex_node
 {
 public:
   Name_resolution_context context;
-  char *db, *db1, *table1, *db2, *table2;      	/* For outer join using .. */
+  char *db;
   Item *where, *having;                         /* WHERE & HAVING clauses */
   Item *prep_where; /* saved WHERE clause for prepared statement processing */
   /* point on lex in which it was created, used in view subquery detection */
   st_lex *parent_lex;
   enum olap_type olap;
-  SQL_LIST	      table_list, group_list;   /* FROM & GROUP BY clauses */
-  List<Item>          item_list; /* list of fields & expressions */
+  /* FROM clause - points to the beginning of the TABLE_LIST::next_local list. */
+  SQL_LIST	      table_list;
+  SQL_LIST	      group_list; /* GROUP BY clause. */
+  List<Item>          item_list;  /* list of fields & expressions */
   List<String>        interval_list, use_index, *use_index_ptr,
 		      ignore_index, *ignore_index_ptr;
   /* 
@@ -491,7 +493,12 @@ public:
   List<TABLE_LIST> top_join_list; /* join list of the top level          */
   List<TABLE_LIST> *join_list;    /* list for the currently parsed join  */
   TABLE_LIST *embedding;          /* table embedding to the above list   */
-  TABLE_LIST *leaf_tables;        /* list of leaves in join table tree   */
+  /*
+    Beginning of the list of leaves in a FROM clause, where the leaves
+    inlcude all base tables including view tables. The tables are connected
+    by TABLE_LIST::next_leaf, so leaf_tables points to the left-most leaf.
+  */
+  TABLE_LIST *leaf_tables;
   const char *type;               /* type of select for EXPLAIN          */
 
   SQL_LIST order_list;                /* ORDER clause */
@@ -593,7 +600,6 @@ public:
   bool init_nested_join(THD *thd);
   TABLE_LIST *end_nested_join(THD *thd);
   TABLE_LIST *nest_last_join(THD *thd);
-  void save_names_for_using_list(TABLE_LIST *tab1, TABLE_LIST *tab2);
   void add_joined_table(TABLE_LIST *table);
   TABLE_LIST *convert_right_join();
   List<Item>* get_item_list();
@@ -735,6 +741,21 @@ typedef struct st_lex
   List<set_var_base>  var_list;
   List<Item_param>    param_list;
   List<LEX_STRING>    view_list; // view list (list of field names in view)
+  /*
+    A stack of name resolution contexts for the query. This stack is used
+    at parse time to set local name resolution contexts for various parts
+    of a query. For example, in a JOIN ... ON (some_condition) clause the
+    Items in 'some_condition' must be resolved only against the operands
+    of the the join, and not against the whole clause. Similarly, Items in
+    subqueries should be resolved against the subqueries (and outer queries).
+    The stack is used in the following way: when the parser detects that
+    all Items in some clause need a local context, it creates a new context
+    and pushes it on the stack. All newly created Items always store the
+    top-most context in the stack. Once the parser leaves the clause that
+    required a local context, the parser pops the top-most context.
+  */
+  List<Name_resolution_context> context_stack;
+
   SQL_LIST	      proc_list, auxilliary_table_list, save_list;
   create_field	      *last_field;
   udf_func udf;
@@ -926,6 +947,21 @@ typedef struct st_lex
     return ( query_tables_own_last ? *query_tables_own_last : 0);
   }
   void cleanup_after_one_table_open();
+
+  void push_context(Name_resolution_context *context)
+  {
+    context_stack.push_front(context);
+  }
+
+  void pop_context()
+  {
+    context_stack.pop();
+  }
+
+  Name_resolution_context *current_context()
+  {
+    return context_stack.head();
+  }
 } LEX;
 
 struct st_lex_local: public st_lex