Bug#28133: Wrong DATE/DATETIME comparison in IN() function.

The IN 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 IN 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 uses either
an object of the in_datetime class or an object of the cmp_item_datetime
class to perform its work. If the IN() function arguments are rows then
row columns are checked whether the DATE/DATETIME comparator should be used
to compare them.
The in_datetime class is used to find occurence of the item to be checked
in the vector of the constant DATE/DATETIME values. The cmp_item_datetime
class is used to compare items one by one in the DATE/DATETIME context.
Both classes obtain values from items with help of the get_datetime_value()
function and cache the left item if it is a constant one.



mysql-test/t/type_datetime.test:
  Added a test case for the bug#28133: Wrong DATE/DATETIME comparison in IN() function.
mysql-test/r/type_datetime.result:
  Added a test case for the bug#28133: Wrong DATE/DATETIME comparison in IN() function.
mysql-test/r/func_in.result:
  A test case result is corrected after the fix for the bug#28133.
sql/item_cmpfunc.h:
  Bug#28133: Wrong DATE/DATETIME comparison in IN() function.
  Two DATE/DATETIME comparison classes are added.
  The in_datetime class is used to find occurence of the item to be checked
  in the vector of the constant DATE/DATETIME values. The cmp_item_datetime
  class is used to compare items one by one in the DATE/DATETIME context.
  Both classes obtain values from items with help of the get_datetime_value()
  function and cache the left item if it is a constant one.
sql/item_cmpfunc.cc:
  Bug#28133: Wrong DATE/DATETIME comparison in IN() function.
  Now IN 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 uses either
  an object of the in_datetime class or an object of the cmp_item_datetime
  class to perform its work. If the IN() function arguments are rows then
  row columns are checked whether the DATE/DATETIME comparator should be used
  to compare them.

1 files changed, 77 insertions, 25 deletions

diff --git a/sql/item_cmpfunc.h b/sql/item_cmpfunc.h
index 761ca90d0a7..79091b9c87d 100644
--- a/sql/item_cmpfunc.h
+++ b/sql/item_cmpfunc.h
@@ -833,6 +833,7 @@ public:
 
 class in_longlong :public in_vector
 {
+protected:
   /*
     Here we declare a temporary variable (tmp) of the same type as the
     elements of this vector. tmp is used in finding if a given value is in 
@@ -866,6 +867,30 @@ public:
   friend int cmp_longlong(void *cmp_arg, packed_longlong *a,packed_longlong *b);
 };
 
+
+/*
+  Class to represent a vector of constant DATE/DATETIME values.
+  Values are obtained with help of the get_datetime_value() function.
+  If the left item is a constant one then its value is cached in the
+  lval_cache variable.
+*/
+class in_datetime :public in_longlong
+{
+public:
+  THD *thd;
+  /* An item used to issue warnings. */
+  Item *warn_item;
+  /* Cache for the left item. */
+  Item *lval_cache;
+
+  in_datetime(Item *warn_item_arg, uint elements)
+    :in_longlong(elements), thd(current_thd), warn_item(warn_item_arg),
+     lval_cache(0) {};
+  void set(uint pos,Item *item);
+  byte *get_value(Item *item);
+  friend int cmp_longlong(void *cmp_arg, packed_longlong *a,packed_longlong *b);
+};
+
 class in_double :public in_vector
 {
   double tmp;
@@ -986,6 +1011,30 @@ public:
   cmp_item *make_same();
 };
 
+/*
+  Compare items in the DATETIME context.
+  Values are obtained with help of the get_datetime_value() function.
+  If the left item is a constant one then its value is cached in the
+  lval_cache variable.
+*/
+class cmp_item_datetime :public cmp_item
+{
+  ulonglong value;
+public:
+  THD *thd;
+  /* Item used for issuing warnings. */
+  Item *warn_item;
+  /* Cache for the left item. */
+  Item *lval_cache;
+
+  cmp_item_datetime(Item *warn_item_arg)
+    :thd(current_thd), warn_item(warn_item_arg), lval_cache(0) {}
+  void store_value(Item *item);
+  int cmp(Item *arg);
+  int compare(cmp_item *ci);
+  cmp_item *make_same();
+};
+
 class cmp_item_real :public cmp_item
 {
   double value;
@@ -1020,31 +1069,6 @@ public:
 };
 
 
-class cmp_item_row :public cmp_item
-{
-  cmp_item **comparators;
-  uint n;
-public:
-  cmp_item_row(): comparators(0), n(0) {}
-  ~cmp_item_row();
-  void store_value(Item *item);
-  int cmp(Item *arg);
-  int compare(cmp_item *arg);
-  cmp_item *make_same();
-  void store_value_by_template(cmp_item *tmpl, Item *);
-};
-
-
-class in_row :public in_vector
-{
-  cmp_item_row tmp;
-public:
-  in_row(uint elements, Item *);
-  ~in_row();
-  void set(uint pos,Item *item);
-  byte *get_value(Item *item);
-};
-
 /* 
    cmp_item for optimized IN with row (right part string, which never
    be changed)
@@ -1120,6 +1144,34 @@ public:
   CHARSET_INFO *compare_collation() { return cmp_collation.collation; }
 };
 
+class cmp_item_row :public cmp_item
+{
+  cmp_item **comparators;
+  uint n;
+public:
+  cmp_item_row(): comparators(0), n(0) {}
+  ~cmp_item_row();
+  void store_value(Item *item);
+  inline void alloc_comparators();
+  int cmp(Item *arg);
+  int compare(cmp_item *arg);
+  cmp_item *make_same();
+  void store_value_by_template(cmp_item *tmpl, Item *);
+  friend void Item_func_in::fix_length_and_dec();
+};
+
+
+class in_row :public in_vector
+{
+  cmp_item_row tmp;
+public:
+  in_row(uint elements, Item *);
+  ~in_row();
+  void set(uint pos,Item *item);
+  byte *get_value(Item *item);
+  friend void Item_func_in::fix_length_and_dec();
+};
+
 /* Functions used by where clause */
 
 class Item_func_isnull :public Item_bool_func