Bug#16377: Wrong DATE/DATETIME comparison in BETWEEN function.

The BETWEEN function was comparing DATE/DATETIME values either as ints or as
strings. Both methods have their disadvantages and may lead to a wrong
result.

Now BETWEEN function checks whether all of its arguments has the STRING result
types and at least one of them is a DATE/DATETIME item. If so it sets up
two Arg_comparator obects to compare with the compare_datetime() comparator
and uses them to compare such items.

Added two Arg_comparator object members and one flag to the
Item_func_between class for the correct DATE/DATETIME comparison.
The Item_func_between::fix_length_and_dec() function now detects whether
it's used for DATE/DATETIME comparison and sets up newly added Arg_comparator
objects to do this.
The Item_func_between::val_int() now uses Arg_comparator objects to perform
correct DATE/DATETIME comparison.
The owner variable of the Arg_comparator class now can be set to NULL if the
caller wants to handle NULL values by itself.
Now the Item_date_add_interval::get_date() function ajusts cached_field type according to the detected type.

mysql-test/r/query_cache.result

@@ -945,25 +945,19 @@ COUNT(*)
 0
 Warnings:
 Warning	1292	Incorrect datetime value: '20050327 invalid' for column 'date' at row 1
-Warning	1292	Incorrect datetime value: '20050327 invalid' for column 'date' at row 1
-Warning	1292	Truncated incorrect INTEGER value: '20050327 invalid'
-Warning	1292	Truncated incorrect INTEGER value: '20050327 invalid'
+Warning	1292	Incorrect datetime value: '20050327 invalid' for column 'date' at row 0
 SELECT COUNT(*) FROM t1 WHERE date BETWEEN '20050326' AND '20050328 invalid';
 COUNT(*)
 0
 Warnings:
 Warning	1292	Incorrect datetime value: '20050328 invalid' for column 'date' at row 1
-Warning	1292	Incorrect datetime value: '20050328 invalid' for column 'date' at row 1
-Warning	1292	Truncated incorrect INTEGER value: '20050328 invalid'
-Warning	1292	Truncated incorrect INTEGER value: '20050328 invalid'
+Warning	1292	Incorrect datetime value: '20050328 invalid' for column 'date' at row 0
 SELECT COUNT(*) FROM t1 WHERE date BETWEEN '20050326' AND '20050327 invalid';
 COUNT(*)
 0
 Warnings:
 Warning	1292	Incorrect datetime value: '20050327 invalid' for column 'date' at row 1
-Warning	1292	Incorrect datetime value: '20050327 invalid' for column 'date' at row 1
-Warning	1292	Truncated incorrect INTEGER value: '20050327 invalid'
-Warning	1292	Truncated incorrect INTEGER value: '20050327 invalid'
+Warning	1292	Incorrect datetime value: '20050327 invalid' for column 'date' at row 0
 show status like "Qcache_queries_in_cache";
 Variable_name	Value
 Qcache_queries_in_cache	0

mysql-test/r/type_datetime.result

@@ -231,3 +231,38 @@ f1	f2	UNIX_TIMESTAMP(f2)	UNIX_TIMESTAMP(f1)	f1 > f2	f1 = f2	f1 < f2
 2001-04-15	2001-04-15 00:00:00	987282000	987282000	0	1	0
 2001-05-20	2001-05-20 01:01:01	990309661	990306000	0	0	1
 drop table t1;
+create table t1 (f1 date, f2 datetime, f3 timestamp);
+insert into t1 values('2001-01-01','2001-01-01 01:01:01','2001-01-01 01:01:01');
+insert into t1 values('2001-02-05','2001-02-05 00:00:00','2001-02-05 01:01:01');
+insert into t1 values('2001-03-10','2001-03-09 01:01:01','2001-03-10 01:01:01');
+insert into t1 values('2001-04-15','2001-04-15 00:00:00','2001-04-15 00:00:00');
+insert into t1 values('2001-05-20','2001-05-20 01:01:01','2001-05-20 01:01:01');
+select f2 from t1 where f2 between '2001-2-5' and '01-04-14';
+f2
+2001-02-05 00:00:00
+2001-03-09 01:01:01
+select f1, f2, f3 from t1 where f1 between f2 and f3;
+f1	f2	f3
+2001-02-05	2001-02-05 00:00:00	2001-02-05 01:01:01
+2001-03-10	2001-03-09 01:01:01	2001-03-10 01:01:01
+2001-04-15	2001-04-15 00:00:00	2001-04-15 00:00:00
+select f1, f2, f3 from t1 where cast(f1 as datetime) between f2 and
+cast(f3 as date);
+f1	f2	f3
+2001-02-05	2001-02-05 00:00:00	2001-02-05 01:01:01
+2001-03-10	2001-03-09 01:01:01	2001-03-10 01:01:01
+2001-04-15	2001-04-15 00:00:00	2001-04-15 00:00:00
+select f2 from t1 where '2001-04-10 12:34:56' between f2 and '01-05-01';
+f2
+2001-01-01 01:01:01
+2001-02-05 00:00:00
+2001-03-09 01:01:01
+select f2, f3 from t1 where '01-03-10' between f2 and f3;
+f2	f3
+2001-03-09 01:01:01	2001-03-10 01:01:01
+select f2 from t1 where DATE(f2) between "2001-4-15" AND "01-4-15";
+f2
+2001-04-15 00:00:00
+SELECT 1 from dual where NOW() BETWEEN CURRENT_DATE() - INTERVAL 1 DAY AND CURRENT_DATE();
+1
+drop table t1;

mysql-test/t/type_datetime.test

@@ -161,3 +161,22 @@ select f1, f2, UNIX_TIMESTAMP(f2), UNIX_TIMESTAMP(f1),
   f1 > f2, f1 = f2, f1 < f2
   from t1;
 drop table t1;
+
+#
+# Bug#16377: Wrong DATE/DATETIME comparison in BETWEEN function.
+#
+create table t1 (f1 date, f2 datetime, f3 timestamp);
+insert into t1 values('2001-01-01','2001-01-01 01:01:01','2001-01-01 01:01:01');
+insert into t1 values('2001-02-05','2001-02-05 00:00:00','2001-02-05 01:01:01');
+insert into t1 values('2001-03-10','2001-03-09 01:01:01','2001-03-10 01:01:01');
+insert into t1 values('2001-04-15','2001-04-15 00:00:00','2001-04-15 00:00:00');
+insert into t1 values('2001-05-20','2001-05-20 01:01:01','2001-05-20 01:01:01');
+select f2 from t1 where f2 between '2001-2-5' and '01-04-14';
+select f1, f2, f3 from t1 where f1 between f2 and f3;
+select f1, f2, f3 from t1 where cast(f1 as datetime) between f2 and
+  cast(f3 as date);
+select f2 from t1 where '2001-04-10 12:34:56' between f2 and '01-05-01';
+select f2, f3 from t1 where '01-03-10' between f2 and f3;
+select f2 from t1 where DATE(f2) between "2001-4-15" AND "01-4-15";
+SELECT 1 from dual where NOW() BETWEEN CURRENT_DATE() - INTERVAL 1 DAY AND CURRENT_DATE();
+drop table t1;

sql/item_cmpfunc.cc

@@ -692,7 +692,7 @@ int Arg_comparator::set_cmp_func(Item_bool_func2 *owner_arg,
         b= (Item **)&b_cache;
       }
     }
-    is_nulls_eq= owner->functype() == Item_func::EQUAL_FUNC;
+    is_nulls_eq= test(owner && owner->functype() == Item_func::EQUAL_FUNC);
     func= &Arg_comparator::compare_datetime;
     return 0;
   }
@@ -700,6 +700,21 @@ int Arg_comparator::set_cmp_func(Item_bool_func2 *owner_arg,
 }
 
 
+void Arg_comparator::set_datetime_cmp_func(Item **a1, Item **b1)
+{
+  thd= current_thd;
+  /* A caller will handle null values by itself. */
+  owner= NULL;
+  a= a1;
+  b= b1;
+  a_type= (*a)->field_type();
+  b_type= (*b)->field_type();
+  a_cache= 0;
+  b_cache= 0;
+  is_nulls_eq= FALSE;
+  func= &Arg_comparator::compare_datetime;
+}
+
 /*
   Retrieves correct DATETIME value from given item.
 
@@ -807,7 +822,8 @@ int Arg_comparator::compare_datetime()
   a_value= get_datetime_value(thd, &a, &a_cache, *b, &is_null);
   if (!is_nulls_eq && is_null)
   {
-    owner->null_value= 1;
+    if (owner)
+      owner->null_value= 1;
     return -1;
   }
 
@@ -815,11 +831,13 @@ int Arg_comparator::compare_datetime()
   b_value= get_datetime_value(thd, &b, &b_cache, *a, &is_null);
   if (is_null)
   {
-    owner->null_value= is_nulls_eq ? 0 : 1;
+    if (owner)
+      owner->null_value= is_nulls_eq ? 0 : 1;
     return is_nulls_eq ? 1 : -1;
   }
 
-  owner->null_value= 0;
+  if (owner)
+    owner->null_value= 0;
 
   /* Compare values. */
   if (is_nulls_eq)
@@ -1674,8 +1692,11 @@ bool Item_func_between::fix_fields(THD *thd, Item **ref)
 
 void Item_func_between::fix_length_and_dec()
 {
-   max_length= 1;
-   THD *thd= current_thd;
+  max_length= 1;
+  THD *thd= current_thd;
+  int i;
+  bool datetime_found= FALSE;
+  compare_as_dates= TRUE;
 
   /*
     As some compare functions are generated after sql_yacc,
@@ -1690,26 +1711,29 @@ void Item_func_between::fix_length_and_dec()
    return;
 
   /*
-    Make a special case of compare with date/time and longlong fields.
-    They are compared as integers, so for const item this time-consuming
-    conversion can be done only once, not for every single comparison
+    Detect the comparison of DATE/DATETIME items.
+    At least one of items should be a DATE/DATETIME item and other items
+    should return the STRING result.
   */
-  if (args[0]->real_item()->type() == FIELD_ITEM &&
-      thd->lex->sql_command != SQLCOM_CREATE_VIEW &&
-      thd->lex->sql_command != SQLCOM_SHOW_CREATE)
+  for (i= 0; i < 3; i++)
   {
-    Field *field=((Item_field*) (args[0]->real_item()))->field;
-    if (field->can_be_compared_as_longlong())
+    if (args[i]->is_datetime())
     {
-      /*
-        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.
+      datetime_found= TRUE;
+      continue;
     }
+    if (args[i]->result_type() == STRING_RESULT)
+      continue;
+    compare_as_dates= FALSE;
+    break;
+  }
+  if (!datetime_found)
+    compare_as_dates= FALSE;
+
+  if (compare_as_dates)
+  {
+    ge_cmp.set_datetime_cmp_func(args, args + 1);
+    le_cmp.set_datetime_cmp_func(args, args + 2);
   }
 }
 
@@ -1717,7 +1741,27 @@ void Item_func_between::fix_length_and_dec()
 longlong Item_func_between::val_int()
 {						// ANSI BETWEEN
   DBUG_ASSERT(fixed == 1);
-  if (cmp_type == STRING_RESULT)
+  if (compare_as_dates)
+  {
+    int ge_res, le_res;
+
+    ge_res= ge_cmp.compare();
+    if ((null_value= args[0]->null_value))
+      return 0;
+    le_res= le_cmp.compare();
+
+    if (!args[1]->null_value && !args[2]->null_value)
+      return (longlong) ((ge_res >= 0 && le_res <=0) != negated);
+    else if (args[1]->null_value)
+    {
+      null_value= le_res > 0;			// not null if false range.
+    }
+    else
+    {
+      null_value= ge_res < 0;
+    }
+  }
+  else if (cmp_type == STRING_RESULT)
   {
     String *value,*a,*b;
     value=args[0]->val_str(&value0);

sql/item_cmpfunc.h

@@ -91,6 +91,7 @@ public:
   static enum enum_date_cmp_type can_compare_as_dates(Item *a, Item *b,
                                                       ulonglong *const_val_arg);
 
+  void set_datetime_cmp_func(Item **a1, Item **b1);
   static arg_cmp_func comparator_matrix [5][2];
 
   friend class Item_func;
@@ -579,8 +580,12 @@ class Item_func_between :public Item_func_opt_neg
 public:
   Item_result cmp_type;
   String value0,value1,value2;
+  /* TRUE <=> arguments will be compared as dates. */
+  bool compare_as_dates;
+  /* Comparators used for DATE/DATETIME comparison. */
+  Arg_comparator ge_cmp, le_cmp;
   Item_func_between(Item *a, Item *b, Item *c)
-    :Item_func_opt_neg(a, b, c) {}
+    :Item_func_opt_neg(a, b, c), compare_as_dates(FALSE) {}
   longlong val_int();
   optimize_type select_optimize() const { return OPTIMIZE_KEY; }
   enum Functype functype() const   { return BETWEEN; }

sql/item_timefunc.cc

@@ -2173,6 +2173,27 @@ bool Item_date_add_interval::get_date(TIME *ltime, uint fuzzy_date)
   default:
     goto null_date;
   }
+
+  /* Adjust cached_field_type according to the detected type. */
+  if (cached_field_type == MYSQL_TYPE_STRING)
+  {
+    switch (ltime->time_type)
+    {
+    case MYSQL_TIMESTAMP_DATE:
+      cached_field_type= MYSQL_TYPE_DATE;
+      break;
+    case MYSQL_TIMESTAMP_DATETIME:
+      cached_field_type= MYSQL_TYPE_DATETIME;
+      break;
+    case MYSQL_TIMESTAMP_TIME:
+      cached_field_type= MYSQL_TYPE_TIME;
+      break;
+    default:
+      /* Shouldn't get here. */
+      DBUG_ASSERT(0);
+      break;
+    }
+  }
   return 0;					// Ok
 
 invalid_date: