subqueries made printable

new EXPLAIN parameter to show real query as it was interpreted
(SCRUM) (WL#1274)


mysql-test/r/subselect.result:
  new explains
mysql-test/r/union.result:
  new explains
mysql-test/t/subselect.test:
  new explains
mysql-test/t/union.test:
  new explains
sql/item.cc:
  fixed printability of Items in SELECT list
sql/item.h:
  fixed printability of Items in SELECT list
sql/item_cmpfunc.cc:
  fixed print()
sql/item_cmpfunc.h:
  fixed print()
sql/item_subselect.cc:
  subqueries made printable
sql/item_subselect.h:
  subqueries made printable
sql/mysql_priv.h:
  union option made looks like options
sql/sql_derived.cc:
  now this link is used
sql/sql_lex.cc:
  subqueries made printable
sql/sql_lex.h:
  subqueries made printable
  new EXPLAIN parameter support
sql/sql_parse.cc:
  new EXPLAIN parameter
sql/sql_select.cc:
  debug output
  new EXPLAIN parameter support
sql/sql_select.h:
  new EXPLAIN parameter support
sql/sql_yacc.yy:
  new EXPLAIN parameter support
  SELECT printability support

1 files changed, 4 insertions, 3 deletions

diff --git a/sql/sql_select.h b/sql/sql_select.h
index 6c17a646ee6..6c1410102fd 100644
--- a/sql/sql_select.h
+++ b/sql/sql_select.h
@@ -151,7 +151,8 @@ class JOIN :public Sql_alloc
   Item_sum  **sum_funcs2, ***sum_funcs_end2;
   Procedure *procedure;
   Item	    *having;
-  Item      *tmp_having; // To store Having when processed temporary table
+  Item      *tmp_having; // To store having when processed temporary table
+  Item      *having_history; // Store having for explain
   uint	    select_options;
   select_result *result;
   TMP_TABLE_PARAM tmp_table_param;
@@ -181,6 +182,7 @@ class JOIN :public Sql_alloc
 
   ORDER *order, *group_list, *proc_param; //hold parameters of mysql_select
   COND *conds;                            // ---"---
+  Item *conds_history;                    // store WHERE for explain
   TABLE_LIST *tables_list;           //hold 'tables' parameter of mysql_selec
   SQL_SELECT *select;                //created in optimisation phase
   Item **ref_pointer_array; //used pointer reference for this select
@@ -217,8 +219,7 @@ class JOIN :public Sql_alloc
     thd= thd_arg;
     sum_funcs= sum_funcs2= 0;
     procedure= 0;
-    having= 0;
-    tmp_having= 0;
+    having= tmp_having= having_history= 0;
     select_options= select_options_arg;
     result= result_arg;
     lock= thd_arg->lock;