fixed excluding st_select_lex from global select list

fixed destroing not well constructed analize object
fixed wrong detection of unions in derived tables

sql/sql_analyse.h

@@ -306,13 +306,14 @@ protected:
 public:
   uint max_tree_elements, max_treemem;
 
-  analyse(select_result *res) :Procedure(res, PROC_NO_SORT), rows(0),
-    output_str_length(0) {}
+  analyse(select_result *res) :Procedure(res, PROC_NO_SORT), f_info(0),
+    rows(0), output_str_length(0) {}
 
   ~analyse()
-  { 
-    for (field_info **f=f_info; f != f_end; f++)
-      delete (*f);
+  {
+    if (f_info)
+      for (field_info **f=f_info; f != f_end; f++)
+	delete (*f);
   }
   virtual void add() {}
   virtual bool change_columns(List<Item> &fields);

sql/sql_derived.cc

@@ -71,7 +71,7 @@ int mysql_derived(THD *thd, LEX *lex, SELECT_LEX_UNIT *unit,
   select_union *derived_result;
   TABLE_LIST *tables= (TABLE_LIST *)sl->table_list.first;
   TMP_TABLE_PARAM tmp_table_param;
-  bool is_union= sl->next_select() && sl->next_select()->linkage == UNION_TYPE;
+  bool is_union= sl->next_select();
   bool is_subsel= sl->first_inner_unit() ? 1: 0;
   SELECT_LEX_NODE *save_current_select= lex->current_select;
   DBUG_ENTER("mysql_derived");

sql/sql_lex.cc

@@ -1098,10 +1098,11 @@ void st_select_lex_node::fast_exclude()
   {
     if ((*link_prev= link_next))
       link_next->link_prev= link_prev;
-    // Remove slave structure
-    for (; slave; slave= slave->next)
-      slave->fast_exclude();
   }
+  // Remove slave structure
+  for (; slave; slave= slave->next)
+    slave->fast_exclude();
+  
 }
 
 /*