MDEV-15664 : sql_mode=ORACLE: Make TRIM return NULL instead of empty string

1 files changed, 66 insertions, 0 deletions

diff --git a/sql/item_strfunc.h b/sql/item_strfunc.h
index da77f29f108..4e1514c5476 100644
--- a/sql/item_strfunc.h
+++ b/sql/item_strfunc.h
@@ -539,6 +539,9 @@ protected:
   String remove;
   String *trimmed_value(String *res, uint32 offset, uint32 length)
   {
+    if (length == 0)
+      return make_empty_result();
+
     tmp_value.set(*res, offset, length);
     /*
       Make sure to return correct charset and collation:
@@ -552,6 +555,7 @@ protected:
   {
     return trimmed_value(res, 0, res->length());
   }
+  virtual const char *func_name_ext() const { return ""; }
 public:
   Item_func_trim(THD *thd, Item *a, Item *b): Item_str_func(thd, a, b) {}
   Item_func_trim(THD *thd, Item *a): Item_str_func(thd, a) {}
@@ -565,6 +569,27 @@ public:
 };
 
 
+class Item_func_trim_oracle :public Item_func_trim
+{
+protected:
+  String *make_empty_result()
+  { null_value= 1; return NULL; }
+  const char *func_name_ext() const { return "_oracle"; }
+public:
+  Item_func_trim_oracle(THD *thd, Item *a, Item *b):
+    Item_func_trim(thd, a, b) {}
+  Item_func_trim_oracle(THD *thd, Item *a): Item_func_trim(thd, a) {}
+  const char *func_name() const { return "trim_oracle"; }
+  void fix_length_and_dec()
+  {
+    Item_func_trim::fix_length_and_dec();
+    maybe_null= true;
+  }
+  Item *get_copy(THD *thd)
+  { return get_item_copy<Item_func_trim_oracle>(thd, this); }
+};
+
+
 class Item_func_ltrim :public Item_func_trim
 {
 public:
@@ -578,6 +603,27 @@ public:
 };
 
 
+class Item_func_ltrim_oracle :public Item_func_ltrim
+{
+protected:
+  String *make_empty_result()
+  { null_value= 1; return NULL; }
+  const char *func_name_ext() const { return "_oracle"; }
+public:
+  Item_func_ltrim_oracle(THD *thd, Item *a, Item *b):
+    Item_func_ltrim(thd, a, b) {}
+  Item_func_ltrim_oracle(THD *thd, Item *a): Item_func_ltrim(thd, a) {}
+  const char *func_name() const { return "ltrim_oracle"; }
+  void fix_length_and_dec()
+  {
+    Item_func_ltrim::fix_length_and_dec();
+    maybe_null= true;
+  }
+  Item *get_copy(THD *thd)
+  { return get_item_copy<Item_func_ltrim_oracle>(thd, this); }
+};
+
+
 class Item_func_rtrim :public Item_func_trim
 {
 public:
@@ -591,6 +637,26 @@ public:
 };
 
 
+class Item_func_rtrim_oracle :public Item_func_rtrim
+{
+protected:
+  String *make_empty_result()
+  { null_value= 1; return NULL; }
+  const char *func_name_ext() const { return "_oracle"; }
+public:
+  Item_func_rtrim_oracle(THD *thd, Item *a, Item *b):
+    Item_func_rtrim(thd, a, b) {}
+  Item_func_rtrim_oracle(THD *thd, Item *a): Item_func_rtrim(thd, a) {}
+  const char *func_name() const { return "rtrim_oracle"; }
+  void fix_length_and_dec()
+  {
+    Item_func_rtrim::fix_length_and_dec();
+    maybe_null= true;
+  }
+  Item *get_copy(THD *thd)
+  { return get_item_copy<Item_func_rtrim_oracle>(thd, this); }
+};
+
 /*
   Item_func_password -- new (4.1.1) PASSWORD() function implementation.
   Returns strcat('*', octet2hex(sha1(sha1(password)))). '*' stands for new