Merge remote-tracking branch 'origin/bb-10.2-ext' into 10.3

TODO: enable MDEV-13049 optimization for 10.3

1 files changed, 37 insertions, 10 deletions

diff --git a/sql/sql_prepare.cc b/sql/sql_prepare.cc
index 7fc6141bcea..775717fe62b 100644
--- a/sql/sql_prepare.cc
+++ b/sql/sql_prepare.cc
@@ -725,13 +725,36 @@ void set_param_date(Item_param *param, uchar **pos, ulong len)
 #endif /*!EMBEDDED_LIBRARY*/
 
 
-static void set_param_str(Item_param *param, uchar **pos, ulong len)
+static void set_param_str_or_null(Item_param *param, uchar **pos, ulong len,
+                                  bool empty_string_is_null)
 {
   ulong length= get_param_length(pos, len);
-  if (length > len)
-    length= len;
-  param->set_str((const char *)*pos, length);
-  *pos+= length;
+  if (length == 0 && empty_string_is_null)
+    param->set_null();
+  else
+  {
+    if (length > len)
+      length= len;
+    param->set_str((const char *) *pos, length);
+    *pos+= length;
+  }
+}
+
+
+static void set_param_str(Item_param *param, uchar **pos, ulong len)
+{
+  set_param_str_or_null(param, pos, len, false);
+}
+
+
+/*
+  set_param_str_empty_is_null : bind empty string as null value
+  when sql_mode=MODE_EMPTY_STRING_IS_NULL
+*/
+static void set_param_str_empty_is_null(Item_param *param, uchar **pos,
+                                        ulong len)
+{
+  set_param_str_or_null(param, pos, len, true);
 }
 
 
@@ -806,7 +829,10 @@ static void setup_one_conversion_function(THD *thd, Item_param *param,
       param->value.cs_info.final_character_set_of_str_value=
         String::needs_conversion(0, fromcs, tocs, &dummy_offset) ?
         tocs : fromcs;
-      param->set_param_func= set_param_str;
+
+      param->set_param_func=
+        (thd->variables.sql_mode & MODE_EMPTY_STRING_IS_NULL) ?
+        set_param_str_empty_is_null : set_param_str;
       /*
         Exact value of max_length is not known unless data is converted to
         charset of connection, so we have to set it later.
@@ -1365,7 +1391,8 @@ static bool mysql_test_insert(Prepared_statement *stmt,
         my_error(ER_WRONG_VALUE_COUNT_ON_ROW, MYF(0), counter);
         goto error;
       }
-      if (setup_fields(thd, Ref_ptr_array(), *values, MARK_COLUMNS_NONE, 0, 0))
+      if (setup_fields(thd, Ref_ptr_array(),
+                       *values, MARK_COLUMNS_NONE, 0, NULL, 0))
         goto error;
     }
   }
@@ -1459,7 +1486,7 @@ static int mysql_test_update(Prepared_statement *stmt,
 #endif
   thd->lex->select_lex.no_wrap_view_item= TRUE;
   res= setup_fields(thd, Ref_ptr_array(),
-                    select->item_list, MARK_COLUMNS_READ, 0, 0);
+                    select->item_list, MARK_COLUMNS_READ, 0, NULL, 0);
   thd->lex->select_lex.no_wrap_view_item= FALSE;
   if (res)
     goto error;
@@ -1471,7 +1498,7 @@ static int mysql_test_update(Prepared_statement *stmt,
   table_list->register_want_access(SELECT_ACL);
 #endif
   if (setup_fields(thd, Ref_ptr_array(),
-                   stmt->lex->value_list, MARK_COLUMNS_NONE, 0, 0) ||
+                   stmt->lex->value_list, MARK_COLUMNS_NONE, 0, NULL, 0) ||
       check_unique_table(thd, table_list))
     goto error;
   /* TODO: here we should send types of placeholders to the client. */
@@ -1646,7 +1673,7 @@ static bool mysql_test_do_fields(Prepared_statement *stmt,
                                      DT_PREPARE | DT_CREATE))
     DBUG_RETURN(TRUE);
   DBUG_RETURN(setup_fields(thd, Ref_ptr_array(),
-                           *values, MARK_COLUMNS_NONE, 0, 0));
+                           *values, MARK_COLUMNS_NONE, 0, NULL, 0));
 }