MDEV-12658 Make the third parameter to LPAD and RPAD optional

1 files changed, 60 insertions, 8 deletions

diff --git a/sql/item_create.cc b/sql/item_create.cc
index 305f62a04b1..f678bb44f21 100644
--- a/sql/item_create.cc
+++ b/sql/item_create.cc
@@ -2260,10 +2260,11 @@ protected:
 };
 
 
-class Create_func_lpad : public Create_func_arg3
+class Create_func_lpad : public Create_native_func
 {
 public:
-  virtual Item *create_3_arg(THD *thd, Item *arg1, Item *arg2, Item *arg3);
+  virtual Item *create_native(THD *thd, LEX_CSTRING *name,
+                              List<Item> *item_list);
 
   static Create_func_lpad s_singleton;
 
@@ -2686,10 +2687,11 @@ protected:
 };
 
 
-class Create_func_rpad : public Create_func_arg3
+class Create_func_rpad : public Create_native_func
 {
 public:
-  virtual Item *create_3_arg(THD *thd, Item *arg1, Item *arg2, Item *arg3);
+  virtual Item *create_native(THD *thd, LEX_CSTRING *name,
+                              List<Item> *item_list);
 
   static Create_func_rpad s_singleton;
 
@@ -5791,9 +5793,34 @@ Create_func_log2::create_1_arg(THD *thd, Item *arg1)
 Create_func_lpad Create_func_lpad::s_singleton;
 
 Item*
-Create_func_lpad::create_3_arg(THD *thd, Item *arg1, Item *arg2, Item *arg3)
+Create_func_lpad::create_native(THD *thd, LEX_CSTRING *name,
+                                List<Item> *item_list)
 {
-  return new (thd->mem_root) Item_func_lpad(thd, arg1, arg2, arg3);
+  Item *func= NULL;
+  int arg_count= item_list ? item_list->elements : 0;
+
+  switch (arg_count) {
+  case 2:
+  {
+    Item *param_1= item_list->pop();
+    Item *param_2= item_list->pop();
+    func= new (thd->mem_root) Item_func_lpad(thd, param_1, param_2);
+    break;
+  }
+  case 3:
+  {
+    Item *param_1= item_list->pop();
+    Item *param_2= item_list->pop();
+    Item *param_3= item_list->pop();
+    func= new (thd->mem_root) Item_func_lpad(thd, param_1, param_2, param_3);
+    break;
+  }
+  default:
+    my_error(ER_WRONG_PARAMCOUNT_TO_NATIVE_FCT, MYF(0), name->str);
+    break;
+  }
+
+  return func;
 }
 
 
@@ -6253,9 +6280,34 @@ Create_func_round::create_native(THD *thd, LEX_CSTRING *name,
 Create_func_rpad Create_func_rpad::s_singleton;
 
 Item*
-Create_func_rpad::create_3_arg(THD *thd, Item *arg1, Item *arg2, Item *arg3)
+Create_func_rpad::create_native(THD *thd, LEX_CSTRING *name,
+                                List<Item> *item_list)
 {
-  return new (thd->mem_root) Item_func_rpad(thd, arg1, arg2, arg3);
+  Item *func= NULL;
+  int arg_count= item_list ? item_list->elements : 0;
+
+  switch (arg_count) {
+  case 2:
+  {
+    Item *param_1= item_list->pop();
+    Item *param_2= item_list->pop();
+    func= new (thd->mem_root) Item_func_rpad(thd, param_1, param_2);
+    break;
+  }
+  case 3:
+  {
+    Item *param_1= item_list->pop();
+    Item *param_2= item_list->pop();
+    Item *param_3= item_list->pop();
+    func= new (thd->mem_root) Item_func_rpad(thd, param_1, param_2, param_3);
+    break;
+  }
+  default:
+    my_error(ER_WRONG_PARAMCOUNT_TO_NATIVE_FCT, MYF(0), name->str);
+    break;
+  }
+
+  return func;
 }