subqueries made printable

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

1 files changed, 155 insertions, 6 deletions

diff --git a/sql/item_subselect.cc b/sql/item_subselect.cc
index 5e0221ad6c7..0703179d92a 100644
--- a/sql/item_subselect.cc
+++ b/sql/item_subselect.cc
@@ -141,17 +141,28 @@ Item::Type Item_subselect::type() const
   return SUBSELECT_ITEM;
 }
 
+
 void Item_subselect::fix_length_and_dec()
 {
   engine->fix_length_and_dec(0);
 }
 
+
 inline table_map Item_subselect::used_tables() const
 {
   return (table_map) (engine->dependent() ? 1L :
 		      (engine->uncacheable() ? RAND_TABLE_BIT : 0L));
 }
 
+
+void Item_subselect::print(String *str)
+{
+  str->append('(');
+  engine->print(str);
+  str->append(')');
+}
+
+
 Item_singlerow_subselect::Item_singlerow_subselect(st_select_lex *select_lex)
   :Item_subselect(), value(0)
 {
@@ -164,17 +175,24 @@ Item_singlerow_subselect::Item_singlerow_subselect(st_select_lex *select_lex)
 }
 
 Item_maxmin_subselect::Item_maxmin_subselect(st_select_lex *select_lex,
-					     bool max)
+					     bool max_arg)
   :Item_singlerow_subselect()
 {
   DBUG_ENTER("Item_maxmin_subselect::Item_maxmin_subselect");
-  init(select_lex, new select_max_min_finder_subselect(this, max));
+  max= max_arg;
+  init(select_lex, new select_max_min_finder_subselect(this, max_arg));
   max_columns= 1;
   maybe_null= 1;
   max_columns= 1;
   DBUG_VOID_RETURN;
 }
 
+void Item_maxmin_subselect::print(String *str)
+{
+  str->append(max?"<max>":"<min>");
+  Item_singlerow_subselect::print(str);
+}
+
 void Item_singlerow_subselect::reset()
 {
   null_value= 1;
@@ -217,7 +235,7 @@ Item_singlerow_subselect::select_transformer(JOIN *join)
     */
     substitution->walk(&Item::remove_dependence_processor,
 		       (byte *) select_lex->outer_select());
-    if (select_lex->where || select_lex->having)
+    if (join->conds || join->having)
     {
       Item *cond;
       if (!join->having)
@@ -337,6 +355,7 @@ String *Item_singlerow_subselect::val_str (String *str)
   }
 }
 
+
 Item_exists_subselect::Item_exists_subselect(st_select_lex *select_lex):
   Item_subselect()
 {
@@ -351,6 +370,14 @@ Item_exists_subselect::Item_exists_subselect(st_select_lex *select_lex):
   DBUG_VOID_RETURN;
 }
 
+
+void Item_exists_subselect::print(String *str)
+{
+  str->append("exists");
+  Item_subselect::print(str);
+}
+
+
 bool Item_in_subselect::test_limit(SELECT_LEX_UNIT *unit)
 {
   if (unit->fake_select_lex &&
@@ -368,7 +395,7 @@ bool Item_in_subselect::test_limit(SELECT_LEX_UNIT *unit)
 
 Item_in_subselect::Item_in_subselect(Item * left_exp,
 				     st_select_lex *select_lex):
-  Item_exists_subselect(), upper_not(0)
+  Item_exists_subselect(), transformed(0), upper_not(0)
 {
   DBUG_ENTER("Item_in_subselect::Item_in_subselect");
   left_expr= left_exp;
@@ -384,8 +411,9 @@ Item_in_subselect::Item_in_subselect(Item * left_exp,
 
 Item_allany_subselect::Item_allany_subselect(Item * left_exp,
 					     compare_func_creator fn,
-					     st_select_lex *select_lex)
-  :Item_in_subselect()
+					     st_select_lex *select_lex,
+					     bool all_arg)
+  :Item_in_subselect(), all(all_arg)
 {
   DBUG_ENTER("Item_in_subselect::Item_in_subselect");
   left_expr= left_exp;
@@ -758,6 +786,7 @@ Item_in_subselect::row_value_transformer(JOIN *join,
 Item_subselect::trans_res
 Item_in_subselect::select_transformer(JOIN *join)
 {
+  transformed= 1;
   if (left_expr->cols() == 1)
     return single_value_transformer(join, left_expr,
 				    &Item_bool_func2::eq_creator);
@@ -765,12 +794,82 @@ Item_in_subselect::select_transformer(JOIN *join)
 }
 
 
+void Item_in_subselect::print(String *str)
+{
+  if (transformed)
+    str->append("<exists>");
+  else
+  {
+    left_expr->print(str);
+    str->append(" in ");
+  }
+  Item_subselect::print(str);
+}
+
+
 Item_subselect::trans_res
 Item_allany_subselect::select_transformer(JOIN *join)
 {
+  transformed= 1;
+  if (upper_not)
+    upper_not->show= 1;
   return single_value_transformer(join, left_expr, func);
 }
 
+
+void Item_allany_subselect::print(String *str)
+{
+  if (transformed)
+    str->append("<exists>");
+  else
+  {
+    left_expr->print(str);
+    str->append(' ');
+    if (all)
+    {
+      if (func ==  &Item_bool_func2::lt_creator)
+	str->append(">=");
+      else if (func ==  &Item_bool_func2::gt_creator)
+	str->append("<=");
+      else if (func ==  &Item_bool_func2::le_creator)
+	str->append('>');
+      else if (func ==  &Item_bool_func2::ge_creator)
+	str->append('<');
+      else if (func ==  &Item_bool_func2::eq_creator)
+	str->append("<>");
+      else if (func ==  &Item_bool_func2::ne_creator)
+	str->append('=');
+      else
+      {
+	DBUG_ASSERT(0);  // Impossible
+      }
+      str->append(" all ");
+    }
+    else
+    {
+      if (func ==  &Item_bool_func2::lt_creator)
+	str->append('<');
+      else if (func ==  &Item_bool_func2::gt_creator)
+	str->append('>');
+      else if (func ==  &Item_bool_func2::le_creator)
+	str->append("<=");
+      else if (func ==  &Item_bool_func2::ge_creator)
+	str->append(">=");
+      else if (func ==  &Item_bool_func2::eq_creator)
+	str->append('=');
+      else if (func ==  &Item_bool_func2::ne_creator)
+	str->append("<>");
+      else
+      {
+	DBUG_ASSERT(0);  // Impossible
+      }
+      str->append(" any ");
+    }
+  }
+  Item_subselect::print(str);
+}
+
+
 subselect_single_select_engine::
 subselect_single_select_engine(st_select_lex *select,
 			       select_subselect *result,
@@ -1098,11 +1197,13 @@ uint subselect_single_select_engine::cols()
   return select_lex->item_list.elements;
 }
 
+
 uint subselect_union_engine::cols()
 {
   return unit->first_select()->item_list.elements;
 }
 
+
 bool subselect_single_select_engine::dependent()
 {
   return select_lex->dependent;
@@ -1113,16 +1214,19 @@ bool subselect_union_engine::dependent()
   return unit->dependent;
 }
 
+
 bool subselect_single_select_engine::uncacheable()
 {
   return select_lex->uncacheable;
 }
 
+
 bool subselect_union_engine::uncacheable()
 {
   return unit->uncacheable;
 }
 
+
 void subselect_single_select_engine::exclude()
 {
   select_lex->master_unit()->exclude_level();
@@ -1133,8 +1237,53 @@ void subselect_union_engine::exclude()
   unit->exclude_level();
 }
 
+
 void subselect_uniquesubquery_engine::exclude()
 {
   //this never should be called
   DBUG_ASSERT(0);
 }
+
+
+void subselect_single_select_engine::print(String *str)
+{
+  select_lex->print(thd, str);
+}
+
+
+void subselect_union_engine::print(String *str)
+{
+  unit->print(str);
+}
+
+
+void subselect_uniquesubquery_engine::print(String *str)
+{
+  str->append("<primary_index_lookup>(");
+  tab->ref.items[0]->print(str);
+  str->append(" in ");
+  str->append(tab->table->real_name);
+  if (cond)
+  {
+    str->append(" where ");
+    cond->print(str);
+  }
+  str->append(')');
+}
+
+
+void subselect_indexsubquery_engine::print(String *str)
+{
+  str->append("<index_lookup>(");
+  tab->ref.items[0]->print(str);
+  str->append(" in ");
+  str->append(tab->table->real_name);
+  if (check_null)
+    str->append(" chicking NULL");
+    if (cond)
+  {
+    str->append(" where ");
+    cond->print(str);
+  }
+  str->append(')');
+}