MDEV-5039: incorrect Item_func_regex::update_used_tables()

Other fix of maybe_null problem and revert of revno: 3608 "MDEV-3873 & MDEV-3876 & MDEV-3912 : Wrong result (extra rows) with ALL subquery from a MERGE view."

17 files changed, 135 insertions, 170 deletions

diff --git a/sql/item.cc b/sql/item.cc
index 5207d7d9ba3..9738a068d88 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -9208,18 +9208,10 @@ table_map Item_ref::used_tables() const
 }
 
 
-void Item_ref::update_used_tables() 
+void Item_ref::update_used_tables()
 {
   if (!get_depended_from())
     (*ref)->update_used_tables();
-  maybe_null|= (*ref)->maybe_null;
-}
-
-void Item_direct_view_ref::update_used_tables()
-{
-  Item_ref::update_used_tables();
-  if (view->table && view->table->maybe_null)
-    maybe_null= TRUE;
 }
 
 table_map Item_direct_view_ref::used_tables() const
diff --git a/sql/item.h b/sql/item.h
index 13f8e359dbd..fd19180f3be 100644
--- a/sql/item.h
+++ b/sql/item.h
@@ -1877,8 +1877,6 @@ public:
   void update_used_tables()
   {
     update_table_bitmaps();
-    if (field && field->table)
-      maybe_null|= field->maybe_null();
   }
   Item *get_tmp_table_item(THD *thd);
   bool collect_item_field_processor(uchar * arg);
@@ -2905,7 +2903,6 @@ public:
   void update_used_tables()
   {
     orig_item->update_used_tables();
-    maybe_null|= orig_item->maybe_null;
   }
   bool const_item() const { return orig_item->const_item(); }
   table_map not_null_tables() const { return orig_item->not_null_tables(); }
@@ -2998,7 +2995,6 @@ public:
   Item *replace_equal_field(uchar *arg);
   table_map used_tables() const;	
   table_map not_null_tables() const;
-  void update_used_tables();
   bool walk(Item_processor processor, bool walk_subquery, uchar *arg)
   { 
     return (*ref)->walk(processor, walk_subquery, arg) ||
diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
index f0069757ee3..a6587fd4c3d 100644
--- a/sql/item_cmpfunc.cc
+++ b/sql/item_cmpfunc.cc
@@ -1352,7 +1352,7 @@ int Arg_comparator::compare_e_row()
 
 void Item_func_truth::fix_length_and_dec()
 {
-  set_persist_maybe_null(0);
+  maybe_null= 0;
   null_value= 0;
   decimals= 0;
   max_length= 1;
@@ -1860,8 +1860,7 @@ longlong Item_func_eq::val_int()
 void Item_func_equal::fix_length_and_dec()
 {
   Item_bool_func2::fix_length_and_dec();
-  set_persist_maybe_null(0);
-  null_value= 0;
+  maybe_null=null_value=0;
 }
 
 longlong Item_func_equal::val_int()
@@ -2001,7 +2000,7 @@ void Item_func_interval::fix_length_and_dec()
       }
     }
   }
-  set_persist_maybe_null(0);
+  maybe_null= 0;
   max_length= 2;
   used_tables_cache|= row->used_tables();
   not_null_tables_cache= row->not_null_tables();
@@ -2688,7 +2687,7 @@ void
 Item_func_nullif::fix_length_and_dec()
 {
   Item_bool_func2::fix_length_and_dec();
-  set_persist_maybe_null(1);
+  maybe_null=1;
   if (args[0])					// Only false if EOM
   {
     max_length=args[0]->max_length;
@@ -4482,8 +4481,6 @@ void Item_cond::update_used_tables()
     item->update_used_tables();
     used_tables_cache|= item->used_tables();
     const_item_cache&= item->const_item();
-    if (!persistent_maybe_null && item->maybe_null)
-      maybe_null= 1;
   }
 }
 
@@ -4662,9 +4659,10 @@ longlong Item_is_not_null_test::val_int()
 */
 void Item_is_not_null_test::update_used_tables()
 {
-  args[0]->update_used_tables();
   if (!args[0]->maybe_null)
     used_tables_cache= 0;			/* is always true */
+  else
+    args[0]->update_used_tables();
 }
 
 
@@ -4947,7 +4945,7 @@ Item_func_regex::fix_fields(THD *thd, Item **ref)
     int comp_res= regcomp(TRUE);
     if (comp_res == -1)
     {						// Will always return NULL
-      set_persist_maybe_null(1);
+      maybe_null=1;
       fixed= 1;
       return FALSE;
     }
@@ -4957,7 +4955,7 @@ Item_func_regex::fix_fields(THD *thd, Item **ref)
     maybe_null= args[0]->maybe_null;
   }
   else
-    set_persist_maybe_null(1);
+    maybe_null=1;
   fixed= 1;
   return FALSE;
 }
@@ -5866,8 +5864,6 @@ void Item_equal::update_used_tables()
     item->update_used_tables();
     used_tables_cache|= item->used_tables();
     const_item_cache&= item->const_item();
-    if (!persistent_maybe_null && item->maybe_null)
-      maybe_null= 1;
   }
 }
 
diff --git a/sql/item_cmpfunc.h b/sql/item_cmpfunc.h
index 37871c31e0b..99d89e16532 100644
--- a/sql/item_cmpfunc.h
+++ b/sql/item_cmpfunc.h
@@ -752,11 +752,6 @@ public:
   my_decimal *decimal_op(my_decimal *);
   bool date_op(MYSQL_TIME *ltime,uint fuzzydate);
   void fix_length_and_dec();
-  void update_used_tables()
-  {
-    Item_func_coalesce::update_used_tables();
-    maybe_null|= args[1]->maybe_null;
-  }
   const char *func_name() const { return "ifnull"; }
   Field *tmp_table_field(TABLE *table);
   uint decimal_precision() const;
@@ -776,11 +771,6 @@ public:
   String *str_op(String *);
   bool fix_fields(THD *, Item **);
   void fix_length_and_dec();
-  void update_used_tables()
-  {
-    Item_func::update_used_tables();
-    maybe_null|= args[1]->maybe_null || args[2]->maybe_null;
-  }
   uint decimal_precision() const;
   const char *func_name() const { return "if"; }
   bool eval_not_null_tables(uchar *opt_arg);
@@ -1244,12 +1234,6 @@ public:
   bool date_op(MYSQL_TIME *ltime, uint fuzzydate);
   bool fix_fields(THD *thd, Item **ref);
   void fix_length_and_dec();
-  void update_used_tables()
-  {
-    Item_func::update_used_tables();
-    if (else_expr_num == -1 || args[else_expr_num]->maybe_null)
-      maybe_null= 1;
-  }
   uint decimal_precision() const;
   table_map not_null_tables() const { return 0; }
   const char *func_name() const { return "case"; }
@@ -1369,14 +1353,13 @@ public:
   enum Functype functype() const { return ISNULL_FUNC; }
   void fix_length_and_dec()
   {
-    decimals=0; max_length=1; set_persist_maybe_null(0);
+    decimals=0; max_length=1; maybe_null=0;
     update_used_tables();
   }
   const char *func_name() const { return "isnull"; }
   /* Optimize case of not_null_column IS NULL */
   virtual void update_used_tables()
   {
-    args[0]->update_used_tables();
     if (!args[0]->maybe_null)
     {
       used_tables_cache= 0;			/* is always false */
@@ -1384,6 +1367,7 @@ public:
     }
     else
     {
+      args[0]->update_used_tables();
       used_tables_cache= args[0]->used_tables();
       const_item_cache= args[0]->const_item();
     }
@@ -1430,7 +1414,7 @@ public:
   enum Functype functype() const { return ISNOTNULL_FUNC; }
   void fix_length_and_dec()
   {
-    decimals=0; max_length=1; set_persist_maybe_null(0);
+    decimals=0; max_length=1; maybe_null=0;
   }
   const char *func_name() const { return "isnotnull"; }
   optimize_type select_optimize() const { return OPTIMIZE_NULL; }
@@ -1501,12 +1485,6 @@ public:
   void cleanup();
   longlong val_int();
   bool fix_fields(THD *thd, Item **ref);
-  void update_used_tables()
-  {
-    Item_bool_func::update_used_tables();
-    if (regex_is_const)
-      maybe_null= 1;
-  }
   const char *func_name() const { return "regexp"; }
 
   virtual inline void print(String *str, enum_query_type query_type)
diff --git a/sql/item_func.cc b/sql/item_func.cc
index 98da660f8a7..c729893dae0 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -86,7 +86,7 @@ void Item_func::set_arguments(List<Item> &list)
 }
 
 Item_func::Item_func(List<Item> &list)
-  :allowed_arg_cols(1), persistent_maybe_null(0)
+  :allowed_arg_cols(1)
 {
   set_arguments(list);
 }
@@ -94,7 +94,6 @@ Item_func::Item_func(List<Item> &list)
 Item_func::Item_func(THD *thd, Item_func *item)
   :Item_result_field(thd, item),
    allowed_arg_cols(item->allowed_arg_cols),
-   persistent_maybe_null(0),
    arg_count(item->arg_count),
    used_tables_cache(item->used_tables_cache),
    not_null_tables_cache(item->not_null_tables_cache),
@@ -424,8 +423,6 @@ void Item_func::update_used_tables()
     args[i]->update_used_tables();
     used_tables_cache|=args[i]->used_tables();
     const_item_cache&=args[i]->const_item();
-    if (!persistent_maybe_null && args[i]->maybe_null)
-      maybe_null= 1;
   }
 }
 
@@ -1657,7 +1654,7 @@ void Item_func_div::fix_length_and_dec()
   case IMPOSSIBLE_RESULT:
     DBUG_ASSERT(0);
   }
-  set_persist_maybe_null(1); // devision by zero
+  maybe_null= 1; // devision by zero
   DBUG_VOID_RETURN;
 }
 
@@ -1692,7 +1689,7 @@ void Item_func_int_div::fix_length_and_dec()
   max_length=args[0]->max_length -
     (argtype == DECIMAL_RESULT || argtype == INT_RESULT ?
      args[0]->decimals : 0);
-  set_persist_maybe_null(1);
+  maybe_null=1;
   unsigned_flag=args[0]->unsigned_flag | args[1]->unsigned_flag;
 }
 
@@ -1773,7 +1770,7 @@ void Item_func_mod::result_precision()
 void Item_func_mod::fix_length_and_dec()
 {
   Item_num_op::fix_length_and_dec();
-  set_persist_maybe_null(1);
+  maybe_null= 1;
   unsigned_flag= args[0]->unsigned_flag;
 }
 
@@ -2952,7 +2949,7 @@ longlong Item_func_field::val_int()
 
 void Item_func_field::fix_length_and_dec()
 {
-  set_persist_maybe_null(0); max_length=3;
+  maybe_null=0; max_length=3;
   cmp_type= args[0]->result_type();
   for (uint i=1; i < arg_count ; i++)
     cmp_type= item_cmp_type(cmp_type, args[i]->result_type());
@@ -5018,7 +5015,7 @@ void Item_func_get_user_var::fix_length_and_dec()
 {
   THD *thd=current_thd;
   int error;
-  set_persist_maybe_null(1);
+  maybe_null=1;
   decimals=NOT_FIXED_DEC;
   max_length=MAX_BLOB_WIDTH;
 
@@ -5224,7 +5221,7 @@ void Item_func_get_system_var::update_null_value()
 void Item_func_get_system_var::fix_length_and_dec()
 {
   char *cptr;
-  set_persist_maybe_null(1);
+  maybe_null= TRUE;
   max_length= 0;
 
   if (var->check_type(var_type))
@@ -5756,7 +5753,7 @@ bool Item_func_match::fix_fields(THD *thd, Item **ref)
   DBUG_ASSERT(fixed == 0);
   Item *UNINIT_VAR(item);                        // Safe as arg_count is > 1
 
-  set_persist_maybe_null(1);
+  maybe_null=1;
   join_key=0;
 
   /*
@@ -6090,7 +6087,7 @@ longlong Item_func_row_count::val_int()
 Item_func_sp::Item_func_sp(Name_resolution_context *context_arg, sp_name *name)
   :Item_func(), context(context_arg), m_name(name), m_sp(NULL), sp_result_field(NULL)
 {
-  set_persist_maybe_null(1);
+  maybe_null= 1;
   m_name->init_qname(current_thd);
   dummy_table= (TABLE*) sql_calloc(sizeof(TABLE)+ sizeof(TABLE_SHARE));
   dummy_table->s= (TABLE_SHARE*) (dummy_table+1);
@@ -6101,7 +6098,7 @@ Item_func_sp::Item_func_sp(Name_resolution_context *context_arg,
                            sp_name *name, List<Item> &list)
   :Item_func(list), context(context_arg), m_name(name), m_sp(NULL),sp_result_field(NULL)
 {
-  set_persist_maybe_null(1);
+  maybe_null= 1;
   m_name->init_qname(current_thd);
   dummy_table= (TABLE*) sql_calloc(sizeof(TABLE)+ sizeof(TABLE_SHARE));
   dummy_table->s= (TABLE_SHARE*) (dummy_table+1);
@@ -6255,7 +6252,7 @@ void Item_func_sp::fix_length_and_dec()
   decimals= sp_result_field->decimals();
   max_length= sp_result_field->field_length;
   collation.set(sp_result_field->charset());
-  set_persist_maybe_null(1);
+  maybe_null= 1;
   unsigned_flag= test(sp_result_field->flags & UNSIGNED_FLAG);
 
   DBUG_VOID_RETURN;
diff --git a/sql/item_func.h b/sql/item_func.h
index 4eb0105376a..80b794f30d5 100644
--- a/sql/item_func.h
+++ b/sql/item_func.h
@@ -38,8 +38,6 @@ protected:
     0 means get this number from first argument
   */
   uint allowed_arg_cols;
-  /* maybe_null can't be changed by parameters or used table state */
-  bool persistent_maybe_null;
 public:
   uint arg_count;
   table_map used_tables_cache, not_null_tables_cache;
@@ -65,13 +63,13 @@ public:
   enum Type type() const { return FUNC_ITEM; }
   virtual enum Functype functype() const   { return UNKNOWN_FUNC; }
   Item_func(void):
-    allowed_arg_cols(1), persistent_maybe_null(0), arg_count(0)
+    allowed_arg_cols(1), arg_count(0)
   {
     with_sum_func= 0;
     with_field= 0;
   }
   Item_func(Item *a):
-    allowed_arg_cols(1), persistent_maybe_null(0), arg_count(1)
+    allowed_arg_cols(1), arg_count(1)
   {
     args= tmp_arg;
     args[0]= a;
@@ -79,7 +77,7 @@ public:
     with_field= a->with_field;
   }
   Item_func(Item *a,Item *b):
-    allowed_arg_cols(1), persistent_maybe_null(0), arg_count(2)
+    allowed_arg_cols(1), arg_count(2)
   {
     args= tmp_arg;
     args[0]= a; args[1]= b;
@@ -87,7 +85,7 @@ public:
     with_field= a->with_field || b->with_field;
   }
   Item_func(Item *a,Item *b,Item *c):
-    allowed_arg_cols(1), persistent_maybe_null(0)
+    allowed_arg_cols(1)
   {
     arg_count= 0;
     if ((args= (Item**) sql_alloc(sizeof(Item*)*3)))
@@ -99,7 +97,7 @@ public:
     }
   }
   Item_func(Item *a,Item *b,Item *c,Item *d):
-    allowed_arg_cols(1), persistent_maybe_null(0)
+    allowed_arg_cols(1)
   {
     arg_count= 0;
     if ((args= (Item**) sql_alloc(sizeof(Item*)*4)))
@@ -113,7 +111,7 @@ public:
     }
   }
   Item_func(Item *a,Item *b,Item *c,Item *d,Item* e):
-    allowed_arg_cols(1), persistent_maybe_null(0)
+    allowed_arg_cols(1)
   {
     arg_count= 5;
     if ((args= (Item**) sql_alloc(sizeof(Item*)*5)))
@@ -305,11 +303,6 @@ public:
     info.bool_function= &Item::restore_to_before_no_rows_in_result;
     walk(&Item::call_bool_func_processor, FALSE, (uchar*) &info);
   }
-  inline void set_persist_maybe_null(bool mb_null)
-  {
-    maybe_null= mb_null;
-    persistent_maybe_null= 1;
-  }
 };
 
 
@@ -582,7 +575,7 @@ public:
   }
   double val_real();
   enum_field_types field_type() const { return MYSQL_TYPE_DOUBLE; }
-  void fix_length_and_dec() { set_persist_maybe_null(1); }
+  void fix_length_and_dec() { maybe_null= 1; }
   const char *func_name() const { return "double_typecast"; }
   virtual void print(String *str, enum_query_type query_type);
 };
@@ -723,7 +716,7 @@ class Item_dec_func :public Item_real_func
   void fix_length_and_dec()
   {
     decimals=NOT_FIXED_DEC; max_length=float_length(decimals);
-    set_persist_maybe_null(1);
+    maybe_null=1;
   }
 };
 
@@ -1047,7 +1040,7 @@ public:
   Item_func_coercibility(Item *a) :Item_int_func(a) {}
   longlong val_int();
   const char *func_name() const { return "coercibility"; }
-  void fix_length_and_dec() { max_length=10; set_persist_maybe_null(0); }
+  void fix_length_and_dec() { max_length=10; maybe_null= 0; }
   table_map not_null_tables() const { return 0; }
 };
 
@@ -1209,7 +1202,7 @@ public:
   {}
   longlong val_int();
   const char *func_name() const { return "benchmark"; }
-  void fix_length_and_dec() { max_length=1; set_persist_maybe_null(0); }
+  void fix_length_and_dec() { max_length=1; maybe_null=0; }
   virtual void print(String *str, enum_query_type query_type);
   bool check_vcol_func_processor(uchar *int_arg) 
   {
@@ -1462,7 +1455,7 @@ public:
   double val_real() { DBUG_ASSERT(fixed == 1); null_value= 1; return 0.0; }
   longlong val_int() { DBUG_ASSERT(fixed == 1); null_value=1; return 0; }
   enum Item_result result_type () const { return STRING_RESULT; }
-  void fix_length_and_dec() { set_persist_maybe_null(1); max_length=0; }
+  void fix_length_and_dec() { maybe_null=1; max_length=0; }
 };
 
 #endif /* HAVE_DLOPEN */
@@ -1483,7 +1476,7 @@ class Item_func_get_lock :public Item_int_func
   Item_func_get_lock(Item *a,Item *b) :Item_int_func(a,b) {}
   longlong val_int();
   const char *func_name() const { return "get_lock"; }
-  void fix_length_and_dec() { max_length=1; set_persist_maybe_null(1);}
+  void fix_length_and_dec() { max_length=1; maybe_null=1;}
   bool check_vcol_func_processor(uchar *int_arg) 
   {
     return trace_unsupported_by_check_vcol_func_processor(func_name());
@@ -1497,7 +1490,7 @@ public:
   Item_func_release_lock(Item *a) :Item_int_func(a) {}
   longlong val_int();
   const char *func_name() const { return "release_lock"; }
-  void fix_length_and_dec() { max_length=1; set_persist_maybe_null(1);}
+  void fix_length_and_dec() { max_length=1; maybe_null=1;}
   bool check_vcol_func_processor(uchar *int_arg) 
   {
     return trace_unsupported_by_check_vcol_func_processor(func_name());
@@ -1514,7 +1507,7 @@ public:
   Item_master_pos_wait(Item *a,Item *b,Item *c) :Item_int_func(a,b,c) {}
   longlong val_int();
   const char *func_name() const { return "master_pos_wait"; }
-  void fix_length_and_dec() { max_length=21; set_persist_maybe_null(1);}
+  void fix_length_and_dec() { max_length=21; maybe_null=1;}
   bool check_vcol_func_processor(uchar *int_arg) 
   {
     return trace_unsupported_by_check_vcol_func_processor(func_name());
@@ -1732,8 +1725,7 @@ public:
   Item_func_inet_aton(Item *a) :Item_int_func(a) {}
   longlong val_int();
   const char *func_name() const { return "inet_aton"; }
-  void fix_length_and_dec()
-  { decimals= 0; max_length= 21; set_persist_maybe_null(1); unsigned_flag= 1; }
+  void fix_length_and_dec() { decimals= 0; max_length= 21; maybe_null= 1; unsigned_flag= 1;}
 };
 
 
@@ -1801,8 +1793,7 @@ public:
   Item_func_is_free_lock(Item *a) :Item_int_func(a) {}
   longlong val_int();
   const char *func_name() const { return "is_free_lock"; }
-  void fix_length_and_dec()
-  { decimals= 0; max_length= 1; set_persist_maybe_null(1); }
+  void fix_length_and_dec() { decimals=0; max_length=1; maybe_null=1;}
   bool check_vcol_func_processor(uchar *int_arg) 
   {
     return trace_unsupported_by_check_vcol_func_processor(func_name());
@@ -1816,8 +1807,7 @@ public:
   Item_func_is_used_lock(Item *a) :Item_int_func(a) {}
   longlong val_int();
   const char *func_name() const { return "is_used_lock"; }
-  void fix_length_and_dec()
-  { decimals= 0; max_length= 10; set_persist_maybe_null(1);}
+  void fix_length_and_dec() { decimals=0; max_length=10; maybe_null=1;}
   bool check_vcol_func_processor(uchar *int_arg) 
   {
     return trace_unsupported_by_check_vcol_func_processor(func_name());
@@ -1840,7 +1830,7 @@ public:
   Item_func_row_count() :Item_int_func() {}
   longlong val_int();
   const char *func_name() const { return "row_count"; }
-  void fix_length_and_dec() { decimals= 0; set_persist_maybe_null(0); }
+  void fix_length_and_dec() { decimals= 0; maybe_null=0; }
   bool check_vcol_func_processor(uchar *int_arg) 
   {
 
@@ -1975,7 +1965,7 @@ public:
   Item_func_found_rows() :Item_int_func() {}
   longlong val_int();
   const char *func_name() const { return "found_rows"; }
-  void fix_length_and_dec() { decimals= 0; set_persist_maybe_null(0); }
+  void fix_length_and_dec() { decimals= 0; maybe_null=0; }
   bool check_vcol_func_processor(uchar *int_arg) 
   {
     return trace_unsupported_by_check_vcol_func_processor(func_name());
diff --git a/sql/item_geofunc.cc b/sql/item_geofunc.cc
index 1168813e275..211140c029b 100644
--- a/sql/item_geofunc.cc
+++ b/sql/item_geofunc.cc
@@ -52,7 +52,7 @@ void Item_geometry_func::fix_length_and_dec()
   collation.set(&my_charset_bin);
   decimals=0;
   max_length= (uint32) 4294967295U;
-  set_persist_maybe_null(1);
+  maybe_null= 1;
 }
 
 
@@ -145,7 +145,7 @@ void Item_func_as_wkt::fix_length_and_dec()
 {
   collation.set(default_charset(), DERIVATION_COERCIBLE, MY_REPERTOIRE_ASCII);
   max_length=MAX_BLOB_WIDTH;
-  set_persist_maybe_null(1);
+  maybe_null= 1;
 }
 
 
diff --git a/sql/item_geofunc.h b/sql/item_geofunc.h
index eae6f425f4d..d2030ee7bb9 100644
--- a/sql/item_geofunc.h
+++ b/sql/item_geofunc.h
@@ -89,7 +89,7 @@ public:
   {
     // "GeometryCollection" is the longest
     max_length= 20;
-    set_persist_maybe_null(1);
+    maybe_null= 1;
   };
 };
 
@@ -224,7 +224,7 @@ public:
   {
     Item_func::print(str, query_type);
   }
-  void fix_length_and_dec() { set_persist_maybe_null(1); }
+  void fix_length_and_dec() { maybe_null= 1; }
   bool is_null() { (void) val_int(); return null_value; }
 };
 
@@ -251,7 +251,7 @@ public:
     Item_func::print(str, query_type);
   }
 
-  void fix_length_and_dec() { set_persist_maybe_null(1); }
+  void fix_length_and_dec() { maybe_null= 1; }
   bool is_null() { (void) val_int(); return null_value; }
 };
 
@@ -342,7 +342,7 @@ public:
   longlong val_int();
   optimize_type select_optimize() const { return OPTIMIZE_NONE; }
   const char *func_name() const { return "st_isempty"; }
-  void fix_length_and_dec() { set_persist_maybe_null(1); }
+  void fix_length_and_dec() { maybe_null= 1; }
 };
 
 class Item_func_issimple: public Item_bool_func
@@ -356,7 +356,7 @@ public:
   longlong val_int();
   optimize_type select_optimize() const { return OPTIMIZE_NONE; }
   const char *func_name() const { return "st_issimple"; }
-  void fix_length_and_dec() { set_persist_maybe_null(1); }
+  void fix_length_and_dec() { maybe_null= 1; }
 };
 
 class Item_func_isclosed: public Item_bool_func
@@ -366,7 +366,7 @@ public:
   longlong val_int();
   optimize_type select_optimize() const { return OPTIMIZE_NONE; }
   const char *func_name() const { return "st_isclosed"; }
-  void fix_length_and_dec() { set_persist_maybe_null(1); }
+  void fix_length_and_dec() { maybe_null= 1; }
 };
 
 class Item_func_dimension: public Item_int_func
@@ -376,7 +376,7 @@ public:
   Item_func_dimension(Item *a): Item_int_func(a) {}
   longlong val_int();
   const char *func_name() const { return "st_dimension"; }
-  void fix_length_and_dec() { max_length= 10; set_persist_maybe_null(1); }
+  void fix_length_and_dec() { max_length= 10; maybe_null= 1; }
 };
 
 class Item_func_x: public Item_real_func
@@ -389,7 +389,7 @@ public:
   void fix_length_and_dec() 
   { 
     Item_real_func::fix_length_and_dec();
-    set_persist_maybe_null(1);
+    maybe_null= 1; 
   }
 };
 
@@ -404,7 +404,7 @@ public:
   void fix_length_and_dec() 
   { 
     Item_real_func::fix_length_and_dec();
-    set_persist_maybe_null(1);
+    maybe_null= 1; 
   }
 };
 
@@ -416,7 +416,7 @@ public:
   Item_func_numgeometries(Item *a): Item_int_func(a) {}
   longlong val_int();
   const char *func_name() const { return "st_numgeometries"; }
-  void fix_length_and_dec() { max_length= 10; set_persist_maybe_null(1); }
+  void fix_length_and_dec() { max_length= 10; maybe_null= 1; }
 };
 
 
@@ -427,7 +427,7 @@ public:
   Item_func_numinteriorring(Item *a): Item_int_func(a) {}
   longlong val_int();
   const char *func_name() const { return "st_numinteriorrings"; }
-  void fix_length_and_dec() { max_length= 10; set_persist_maybe_null(1); }
+  void fix_length_and_dec() { max_length= 10; maybe_null= 1; }
 };
 
 
@@ -438,7 +438,7 @@ public:
   Item_func_numpoints(Item *a): Item_int_func(a) {}
   longlong val_int();
   const char *func_name() const { return "st_numpoints"; }
-  void fix_length_and_dec() { max_length= 10; set_persist_maybe_null(1); }
+  void fix_length_and_dec() { max_length= 10; maybe_null= 1; }
 };
 
 
@@ -452,7 +452,7 @@ public:
   void fix_length_and_dec() 
   { 
     Item_real_func::fix_length_and_dec();
-    set_persist_maybe_null(1);
+    maybe_null= 1; 
   }
 };
 
@@ -467,7 +467,7 @@ public:
   void fix_length_and_dec() 
   { 
     Item_real_func::fix_length_and_dec();
-    set_persist_maybe_null(1);
+    maybe_null= 1; 
   }
 };
 
@@ -479,7 +479,7 @@ public:
   Item_func_srid(Item *a): Item_int_func(a) {}
   longlong val_int();
   const char *func_name() const { return "srid"; }
-  void fix_length_and_dec() { max_length= 10; set_persist_maybe_null(1); }
+  void fix_length_and_dec() { max_length= 10; maybe_null= 1; }
 };
 
 
diff --git a/sql/item_strfunc.cc b/sql/item_strfunc.cc
index 50ca7d91a53..a21dd9cc02a 100644
--- a/sql/item_strfunc.cc
+++ b/sql/item_strfunc.cc
@@ -272,7 +272,7 @@ String *Item_func_aes_decrypt::val_str(String *str)
 void Item_func_aes_decrypt::fix_length_and_dec()
 {
    max_length=args[0]->max_length;
-   set_persist_maybe_null(1);
+   maybe_null= 1;
 }
 
 
@@ -435,7 +435,7 @@ void Item_func_concat::fix_length_and_dec()
   if (max_result_length >= MAX_BLOB_WIDTH)
   {
     max_result_length= MAX_BLOB_WIDTH;
-    set_persist_maybe_null(1);
+    maybe_null= 1;
   }
   max_length= (ulong) max_result_length;
 }
@@ -795,7 +795,7 @@ void Item_func_concat_ws::fix_length_and_dec()
   if (max_result_length >= MAX_BLOB_WIDTH)
   {
     max_result_length= MAX_BLOB_WIDTH;
-    set_persist_maybe_null(1);
+    maybe_null= 1;
   }
   max_length= (ulong) max_result_length;
 }
@@ -997,7 +997,7 @@ void Item_func_replace::fix_length_and_dec()
   if (max_result_length >= MAX_BLOB_WIDTH)
   {
     max_result_length= MAX_BLOB_WIDTH;
-    set_persist_maybe_null(1);
+    maybe_null= 1;
   }
   max_length= (ulong) max_result_length;
   
@@ -1081,7 +1081,7 @@ void Item_func_insert::fix_length_and_dec()
   if (max_result_length >= MAX_BLOB_WIDTH)
   {
     max_result_length= MAX_BLOB_WIDTH;
-    set_persist_maybe_null(1);
+    maybe_null= 1;
   }
   max_length= (ulong) max_result_length;
 }
@@ -2186,7 +2186,7 @@ void Item_func_elt::fix_length_and_dec()
     set_if_bigger(max_length,args[i]->max_length);
     set_if_bigger(decimals,args[i]->decimals);
   }
-  set_persist_maybe_null(1);			  // NULL if wrong first arg
+  maybe_null=1;					// NULL if wrong first arg
 }
 
 
@@ -2366,14 +2366,14 @@ void Item_func_repeat::fix_length_and_dec()
     if (max_result_length >= MAX_BLOB_WIDTH)
     {
       max_result_length= MAX_BLOB_WIDTH;
-      set_persist_maybe_null(1);
+      maybe_null= 1;
     }
     max_length= (ulong) max_result_length;
   }
   else
   {
     max_length= MAX_BLOB_WIDTH;
-    set_persist_maybe_null(1);
+    maybe_null= 1;
   }
 }
 
@@ -2458,14 +2458,14 @@ void Item_func_rpad::fix_length_and_dec()
     if (length >= MAX_BLOB_WIDTH)
     {
       length= MAX_BLOB_WIDTH;
-      set_persist_maybe_null(1);
+      maybe_null= 1;
     }
     max_length= (ulong) length;
   }
   else
   {
     max_length= MAX_BLOB_WIDTH;
-    set_persist_maybe_null(1);
+    maybe_null= 1;
   }
 }
 
@@ -2577,14 +2577,14 @@ void Item_func_lpad::fix_length_and_dec()
     if (length >= MAX_BLOB_WIDTH)
     {
       length= MAX_BLOB_WIDTH;
-      set_persist_maybe_null(1);
+      maybe_null= 1;
     }
     max_length= (ulong) length;
   }
   else
   {
     max_length= MAX_BLOB_WIDTH;
-    set_persist_maybe_null(1);
+    maybe_null= 1;
   }
 }
 
@@ -3499,7 +3499,7 @@ bool Item_func_dyncol_create::fix_fields(THD *thd, Item **ref)
 
 void Item_func_dyncol_create::fix_length_and_dec()
 {
-  set_persist_maybe_null(1);
+  maybe_null= TRUE;
   collation.set(&my_charset_bin);
   decimals= 0;
 }
diff --git a/sql/item_strfunc.h b/sql/item_strfunc.h
index 44eeb1ef876..bb2fc0d9a33 100644
--- a/sql/item_strfunc.h
+++ b/sql/item_strfunc.h
@@ -319,7 +319,7 @@ public:
   String *val_str(String *);
   void fix_length_and_dec()
   {
-    set_persist_maybe_null(1);
+    maybe_null=1;
     /* 9 = MAX ((8- (arg_len % 8)) + 1) */
     max_length = args[0]->max_length + 9;
   }
@@ -335,7 +335,7 @@ public:
   String *val_str(String *);
   void fix_length_and_dec()
   {
-    set_persist_maybe_null(1);
+    maybe_null=1;
     /* 9 = MAX ((8- (arg_len % 8)) + 1) */
     max_length = args[0]->max_length - 9;
   }
@@ -361,7 +361,7 @@ public:
     constructor_helper();
   }
   String *val_str(String *);
-  void fix_length_and_dec() { set_persist_maybe_null(1); max_length = 13; }
+  void fix_length_and_dec() { maybe_null=1; max_length = 13; }
   const char *func_name() const { return "encrypt"; }
   bool check_vcol_func_processor(uchar *int_arg) 
   {
@@ -431,7 +431,7 @@ public:
   void fix_length_and_dec()
   {
     max_length= MAX_FIELD_NAME * system_charset_info->mbmaxlen;
-    set_persist_maybe_null(1);
+    maybe_null=1;
   }
   const char *func_name() const { return "database"; }
   const char *fully_qualified_func_name() const { return "database()"; }
@@ -589,7 +589,7 @@ public:
   {
     collation.set(default_charset());
     max_length=64;
-    set_persist_maybe_null(1);
+    maybe_null= 1;
   }
 };
 
@@ -616,7 +616,7 @@ public:
   Item_func_unhex(Item *a) :Item_str_func(a) 
   { 
     /* there can be bad hex strings */
-    set_persist_maybe_null(1);
+    maybe_null= 1; 
   }
   const char *func_name() const { return "unhex"; }
   String *val_str(String *);
@@ -662,7 +662,7 @@ public:
   void fix_length_and_dec()
   {
     collation.set(&my_charset_bin, DERIVATION_COERCIBLE);
-    set_persist_maybe_null(1);
+    maybe_null=1;
     max_length=MAX_BLOB_WIDTH;
   }
   bool check_vcol_func_processor(uchar *int_arg) 
@@ -695,7 +695,7 @@ public:
   { 
     decimals= 0; 
     max_length= 3 * 8 + 7; 
-    set_persist_maybe_null(1);
+    maybe_null= 1;
   }
 };
 
@@ -786,7 +786,7 @@ public:
   {
      collation.set(system_charset_info);
      max_length= 64 * collation.collation->mbmaxlen; // should be enough
-     set_persist_maybe_null(0);
+     maybe_null= 0;
   };
   table_map not_null_tables() const { return 0; }
 };
@@ -801,7 +801,7 @@ public:
   {
      collation.set(system_charset_info);
      max_length= 64 * collation.collation->mbmaxlen; // should be enough
-     set_persist_maybe_null(0);
+     maybe_null= 0;
   };
   table_map not_null_tables() const { return 0; }
 };
@@ -847,8 +847,7 @@ class Item_func_uncompress: public Item_str_func
   String buffer;
 public:
   Item_func_uncompress(Item *a): Item_str_func(a){}
-  void fix_length_and_dec()
-  { set_persist_maybe_null(1); max_length= MAX_BLOB_WIDTH; }
+  void fix_length_and_dec(){ maybe_null= 1; max_length= MAX_BLOB_WIDTH; }
   const char *func_name() const{return "uncompress";}
   String *val_str(String *) ZLIB_DEPENDED_FUNCTION
 };
@@ -920,7 +919,7 @@ public:
     max_length= MAX_DYNAMIC_COLUMN_LENGTH;
   }
   void fix_length_and_dec()
-  { set_persist_maybe_null(1); }
+  { maybe_null= 1; }
   /* Mark that collation can change between calls */
   bool dynamic_result() { return 1; }
 
@@ -939,8 +938,7 @@ class Item_func_dyncol_list: public Item_str_func
 {
 public:
   Item_func_dyncol_list(Item *str) :Item_str_func(str) {};
-  void fix_length_and_dec()
-  { set_persist_maybe_null(1); max_length= MAX_BLOB_WIDTH; };
+  void fix_length_and_dec() { maybe_null= 1; max_length= MAX_BLOB_WIDTH; };
   const char *func_name() const{ return "column_list"; }
   String *val_str(String *);
 };
diff --git a/sql/item_timefunc.cc b/sql/item_timefunc.cc
index 37a9a42f392..6c304946abc 100644
--- a/sql/item_timefunc.cc
+++ b/sql/item_timefunc.cc
@@ -875,7 +875,7 @@ void Item_func_monthname::fix_length_and_dec()
   collation.set(cs, DERIVATION_COERCIBLE, repertoire);
   decimals=0;
   max_length= locale->max_month_name_length * collation.collation->mbmaxlen;
-  set_persist_maybe_null(1);
+  maybe_null=1; 
 }
 
 
@@ -1025,7 +1025,7 @@ void Item_func_dayname::fix_length_and_dec()
   collation.set(cs, DERIVATION_COERCIBLE, repertoire);
   decimals=0;
   max_length= locale->max_day_name_length * collation.collation->mbmaxlen;
-  set_persist_maybe_null(1);
+  maybe_null=1; 
 }
 
 
@@ -1407,7 +1407,7 @@ void Item_func_curdate::fix_length_and_dec()
   ltime.hour= ltime.minute= ltime.second= 0;
   ltime.time_type= MYSQL_TIMESTAMP_DATE;
   Item_datefunc::fix_length_and_dec();
-  set_persist_maybe_null(0);
+  maybe_null= false;
 }
 
 /**
@@ -1646,7 +1646,7 @@ void Item_func_date_format::fix_length_and_dec()
                    collation.collation->mbmaxlen;
     set_if_smaller(max_length,MAX_BLOB_WIDTH);
   }
-  set_persist_maybe_null(1);				// If wrong date
+  maybe_null=1;					// If wrong date
 }
 
 
@@ -2014,7 +2014,7 @@ void Item_extract::print(String *str, enum_query_type query_type)
 
 void Item_extract::fix_length_and_dec()
 {
-  set_persist_maybe_null(1);					// If wrong date
+  maybe_null=1;					// If wrong date
   switch (int_type) {
   case INTERVAL_YEAR:		max_length=4; date_value=1; break;
   case INTERVAL_YEAR_MONTH:	max_length=6; date_value=1; break;
diff --git a/sql/item_timefunc.h b/sql/item_timefunc.h
index 19a9ac12985..20365d4f25d 100644
--- a/sql/item_timefunc.h
+++ b/sql/item_timefunc.h
@@ -67,7 +67,7 @@ public:
   { 
     decimals=0; 
     max_length=6*MY_CHARSET_BIN_MB_MAXLEN;
-    set_persist_maybe_null(1);
+    maybe_null=1; 
   }
   enum_monotonicity_info get_monotonicity_info() const;
   longlong val_int_endpoint(bool left_endp, bool *incl_endp);
@@ -90,7 +90,7 @@ public:
   { 
     decimals=0; 
     max_length=2*MY_CHARSET_BIN_MB_MAXLEN;
-    set_persist_maybe_null(1);
+    maybe_null=1; 
   }
   bool check_partition_func_processor(uchar *int_arg) {return FALSE;}
   bool check_vcol_func_processor(uchar *int_arg) { return FALSE;}
@@ -123,7 +123,7 @@ public:
     collation.set(&my_charset_bin);
     decimals=0;
     max_length=2*MY_CHARSET_BIN_MB_MAXLEN;
-    set_persist_maybe_null(1);
+    maybe_null=1; 
   }
   bool check_partition_func_processor(uchar *int_arg) {return FALSE;}
   bool check_vcol_func_processor(uchar *int_arg) { return FALSE;}
@@ -158,7 +158,7 @@ public:
   { 
     decimals=0;
     max_length=3*MY_CHARSET_BIN_MB_MAXLEN;
-    set_persist_maybe_null(1);
+    maybe_null=1; 
   }
   bool check_partition_func_processor(uchar *int_arg) {return FALSE;}
   bool check_vcol_func_processor(uchar *int_arg) { return FALSE;}
@@ -179,7 +179,7 @@ public:
   {
     decimals=0;
     max_length=2*MY_CHARSET_BIN_MB_MAXLEN;
-    set_persist_maybe_null(1);
+    maybe_null=1;
   }
   bool check_partition_func_processor(uchar *int_arg) {return FALSE;}
   bool check_vcol_func_processor(uchar *int_arg) { return FALSE;}
@@ -200,7 +200,7 @@ public:
   {
     decimals=0;
     max_length=2*MY_CHARSET_BIN_MB_MAXLEN;
-    set_persist_maybe_null(1);
+    maybe_null=1;
   }
   bool check_partition_func_processor(uchar *int_arg) {return FALSE;}
   bool check_vcol_func_processor(uchar *int_arg) { return FALSE;}
@@ -221,7 +221,7 @@ public:
   { 
      decimals=0;
      max_length=1*MY_CHARSET_BIN_MB_MAXLEN;
-     set_persist_maybe_null(1);
+     maybe_null=1;
   }
   bool check_partition_func_processor(uchar *int_arg) {return FALSE;}
   bool check_vcol_func_processor(uchar *int_arg) { return FALSE;}
@@ -242,7 +242,7 @@ public:
   { 
     decimals=0;
     max_length=2*MY_CHARSET_BIN_MB_MAXLEN;
-    set_persist_maybe_null(1);
+    maybe_null=1;
   }
   bool check_partition_func_processor(uchar *int_arg) {return FALSE;}
   bool check_vcol_func_processor(uchar *int_arg) { return FALSE;}
@@ -263,7 +263,7 @@ public:
   { 
     decimals=0;
     max_length=2*MY_CHARSET_BIN_MB_MAXLEN;
-    set_persist_maybe_null(1);
+    maybe_null=1;
   }
 };
 
@@ -277,7 +277,7 @@ public:
   { 
     decimals=0;
     max_length=6*MY_CHARSET_BIN_MB_MAXLEN;
-    set_persist_maybe_null(1);
+    maybe_null=1;
   }
   bool check_partition_func_processor(uchar *int_arg) {return FALSE;}
   bool check_vcol_func_processor(uchar *int_arg) { return FALSE;}
@@ -300,7 +300,7 @@ public:
   { 
     decimals=0;
     max_length=4*MY_CHARSET_BIN_MB_MAXLEN;
-    set_persist_maybe_null(1);
+    maybe_null=1;
   }
   bool check_partition_func_processor(uchar *int_arg) {return FALSE;}
   bool check_vcol_func_processor(uchar *int_arg) { return FALSE;}
@@ -335,7 +335,7 @@ public:
     collation.set(&my_charset_bin);
     decimals=0;
     max_length=1*MY_CHARSET_BIN_MB_MAXLEN;
-    set_persist_maybe_null(1);
+    maybe_null=1;
   }
   bool check_partition_func_processor(uchar *int_arg) {return FALSE;}
   bool check_vcol_func_processor(uchar *int_arg) { return FALSE;}
@@ -372,7 +372,7 @@ public:
       decimals= args[0]->temporal_precision(arg0_expected_type());
     set_if_smaller(decimals, TIME_SECOND_PART_DIGITS);
     max_length=17 + (decimals ? decimals + 1 : 0);
-    set_persist_maybe_null(1);
+    maybe_null= true;
   }
   void find_num_type()
   { cached_result_type= decimals ? DECIMAL_RESULT : INT_RESULT; }
@@ -424,7 +424,7 @@ public:
   const char *func_name() const { return "time_to_sec"; }
   void fix_num_length_and_dec()
   {
-    set_persist_maybe_null(1);
+    maybe_null= true;
     Item_func_seconds_hybrid::fix_num_length_and_dec();
   }
   bool check_partition_func_processor(uchar *int_arg) {return FALSE;}
@@ -458,8 +458,8 @@ public:
   int save_in_field(Field *field, bool no_conversions)
   { return save_date_in_field(field); }
   void fix_length_and_dec()
-  { 
-    set_persist_maybe_null(1);
+  {
+    maybe_null= true;
     max_length= mysql_temporal_int_part_length(field_type());
     if (decimals)
     {
@@ -475,7 +475,7 @@ public:
       We set maybe_null to 1 as default as any bad argument with date or
       time can get us to return NULL.
     */ 
-    set_persist_maybe_null(1);
+    maybe_null= 1;
   }
 };
 
@@ -512,7 +512,7 @@ public:
   {
     store_now_in_TIME(&ltime);
     Item_timefunc::fix_length_and_dec();
-    set_persist_maybe_null(0);
+    maybe_null= false;
   }
   bool get_date(MYSQL_TIME *res, uint fuzzy_date);
   /* 
@@ -594,7 +594,7 @@ public:
   {
     store_now_in_TIME(&ltime);
     Item_temporal_func::fix_length_and_dec();
-    set_persist_maybe_null(0);
+    maybe_null= false;
   }
   bool get_date(MYSQL_TIME *res, uint fuzzy_date);
   virtual void store_now_in_TIME(MYSQL_TIME *now_time)=0;
@@ -941,7 +941,7 @@ public:
   void fix_length_and_dec() 
   { 
     decimals=0;
-    set_persist_maybe_null(1);
+    maybe_null=1;
   }
   bool check_partition_func_processor(uchar *int_arg) {return FALSE;}
   bool check_vcol_func_processor(uchar *int_arg) { return FALSE;}
@@ -963,7 +963,7 @@ public:
   void fix_length_and_dec()
   {
     decimals=0;
-    set_persist_maybe_null(1);
+    maybe_null=1;
   }
   virtual void print(String *str, enum_query_type query_type);
 };
@@ -985,7 +985,7 @@ public:
   const char *func_name() const { return "get_format"; }
   void fix_length_and_dec()
   {
-    set_persist_maybe_null(1);
+    maybe_null= 1;
     decimals=0;
     max_length=17*MY_CHARSET_BIN_MB_MAXLEN;
   }
diff --git a/sql/item_xmlfunc.cc b/sql/item_xmlfunc.cc
index 4c12e6528ac..a873cc0b277 100644
--- a/sql/item_xmlfunc.cc
+++ b/sql/item_xmlfunc.cc
@@ -2579,7 +2579,6 @@ void Item_xml_str_func::fix_length_and_dec()
   int rc;
 
   nodeset_func= 0;
-  set_persist_maybe_null(1);
 
   if (agg_arg_charsets(collation, args, arg_count, MY_COLL_CMP_CONV, 1))
     return;
diff --git a/sql/item_xmlfunc.h b/sql/item_xmlfunc.h
index be56a83349f..ce33d161c79 100644
--- a/sql/item_xmlfunc.h
+++ b/sql/item_xmlfunc.h
@@ -30,10 +30,14 @@ protected:
 public:
   Item_xml_str_func(Item *a, Item *b): 
     Item_str_func(a,b) 
-  {}
+  {
+    maybe_null= TRUE;
+  }
   Item_xml_str_func(Item *a, Item *b, Item *c): 
     Item_str_func(a,b,c) 
-  {}
+  {
+    maybe_null= TRUE;
+  }
   void fix_length_and_dec();
   String *parse_xml(String *raw_xml, String *parsed_xml_buf);
   bool check_vcol_func_processor(uchar *int_arg) 
diff --git a/sql/sql_derived.cc b/sql/sql_derived.cc
index afc2dea359a..a8bfc8a11a7 100644
--- a/sql/sql_derived.cc
+++ b/sql/sql_derived.cc
@@ -622,6 +622,15 @@ bool mysql_derived_prepare(THD *thd, LEX *lex, TABLE_LIST *derived)
     sl->context.outer_context= 0;
     // Prepare underlying views/DT first.
     sl->handle_derived(lex, DT_PREPARE);
+
+    if (derived->outer_join)
+    {
+      /* Mark that table is part of OUTER JOIN and fields may be NULL */
+      for (TABLE_LIST *cursor= (TABLE_LIST*) sl->table_list.first;
+           cursor;
+           cursor= cursor->next_local)
+        cursor->outer_join|= JOIN_TYPE_OUTER;
+    }
   }
 
   unit->derived= derived;
@@ -716,6 +725,10 @@ exit:
     /* Add new temporary table to list of open derived tables */
     table->next= thd->derived_tables;
     thd->derived_tables= table;
+
+    /* If table is used by a left join, mark that any column may be null */
+    if (derived->outer_join)
+      table->maybe_null= 1;
   }
   if (arena)
     thd->restore_active_arena(arena, &backup);
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 7f0362e6555..99157d9201b 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -8269,7 +8269,7 @@ make_outerjoin_info(JOIN *join)
     TABLE_LIST *tbl= table->pos_in_table_list;
     TABLE_LIST *embedding= tbl->embedding;
 
-    if (tbl->outer_join)
+    if (tbl->outer_join & (JOIN_TYPE_LEFT | JOIN_TYPE_RIGHT))
     {
       /* 
         Table tab is the only one inner table for outer join.
@@ -12586,7 +12586,8 @@ simplify_joins(JOIN *join, List<TABLE_LIST> *join_list, COND *conds, bool top,
       table->embedding->nested_join->not_null_tables|= not_null_tables;
     }
 
-    if (!table->outer_join || (used_tables & not_null_tables))
+    if (!(table->outer_join & (JOIN_TYPE_LEFT | JOIN_TYPE_RIGHT)) ||
+        (used_tables & not_null_tables))
     {
       /* 
         For some of the inner tables there are conjunctive predicates
diff --git a/sql/table.h b/sql/table.h
index 49b9fe2a1b9..c3524ad3adf 100644
--- a/sql/table.h
+++ b/sql/table.h
@@ -1202,6 +1202,7 @@ typedef struct st_schema_table
 
 #define JOIN_TYPE_LEFT	1
 #define JOIN_TYPE_RIGHT	2
+#define JOIN_TYPE_OUTER 4	/* Marker that this is an outer join */
 
 #define VIEW_SUID_INVOKER               0
 #define VIEW_SUID_DEFINER               1