Bug#28778: Wrong result of BETWEEN when comparing a DATETIME field with an

integer constants.

This bug is introduced by the fix for bug#16377. Before the fix the 
Item_func_between::fix_length_and_dec method converted the second and third
arguments to the type of the first argument if they were constant and the first
argument is of the DATE/DATETIME type. That approach worked well for integer
constants and sometimes produced bad result for string constants. The fix for
the bug#16377 wrongly removed that code at all and as a result of this the
comparison of a DATETIME field and an integer constant was carried out in a
wrong way and sometimes led to wrong result sets.

Now the Item_func_between::fix_length_and_dec method converts the second and
third arguments to the type of the first argument if they are constant, the
first argument is of the DATE/DATETIME type and the DATETIME comparator isn't
applicable.


sql/item_cmpfunc.cc:
  Bug#28778: Wrong result of BETWEEN when comparing a DATETIME field with an
  integer constants.
  Now the Item_func_between::fix_length_and_dec method converts the second and
  third arguments to the type of the first argument if they are constant, the
  first argument is of the DATE/DATETIME type and the DATETIME comparator isn't
  applicable.
mysql-test/r/type_datetime.result:
  Added a test case for the bug#28778: Wrong result of BETWEEN when comparing a DATETIME
  field with an integer constants.
mysql-test/t/type_datetime.test:
  Added a test case for the bug#28778: Wrong result of BETWEEN when comparing a DATETIME
  field with an integer constants.

1 files changed, 17 insertions, 0 deletions

diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
index 06c825334c2..919015140c1 100644
--- a/sql/item_cmpfunc.cc
+++ b/sql/item_cmpfunc.cc
@@ -1755,6 +1755,23 @@ void Item_func_between::fix_length_and_dec()
     ge_cmp.set_datetime_cmp_func(args, args + 1);
     le_cmp.set_datetime_cmp_func(args, args + 2);
   }
+  else if (args[0]->real_item()->type() == FIELD_ITEM &&
+           thd->lex->sql_command != SQLCOM_CREATE_VIEW &&
+           thd->lex->sql_command != SQLCOM_SHOW_CREATE)
+  {
+    Field *field=((Item_field*) (args[0]->real_item()))->field;
+    if (field->can_be_compared_as_longlong())
+    {
+      /*
+        The following can't be recoded with || as convert_constant_item
+        changes the argument
+      */
+      if (convert_constant_item(thd, field,&args[1]))
+        cmp_type=INT_RESULT;			// Works for all types.
+      if (convert_constant_item(thd, field,&args[2]))
+        cmp_type=INT_RESULT;			// Works for all types.
+    }
+  }
 }