Commit 3507a52e authored by unknown's avatar unknown
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A fix and test case for Bug#6297 "prepared statement, wrong handling 

 of <parameter> IS NULL":
we must not only set Item::null_value in Item_param, but implement
Item_param::is_null() to work well with IS NULL/IS NOT NULL clauses.


mysql-test/r/ps.result:
  Test case for Bug#6297: test results fixed.
mysql-test/t/ps.test:
  A test case for Bug#6297 "prepared statement, wrong handling of 
  <parameter> IS NULL"
sql/item.h:
  A fix for Bug#6297: we must not only set null_value in Item_param, but
  also implement Item_param::is_null() to work well with  IS NULL/
  IS NOT NULL.
  Item::is_null() commented.
parent 99d2d100

mysql-test/r/ps.result

+21 −0
Original line number Diff line number Diff line
@@ -450,3 +450,24 @@ PREPARE stmt FROM 'UPDATE t1 AS P1 INNER JOIN (SELECT N FROM t1 GROUP BY N HAVIN 
EXECUTE stmt;

DEALLOCATE PREPARE stmt;

DROP TABLE t1;

prepare stmt from "select ? is null, ? is not null, ?";

select @no_such_var is null, @no_such_var is not null, @no_such_var;

@no_such_var is null	@no_such_var is not null	@no_such_var

1	0	NULL

execute stmt using @no_such_var, @no_such_var, @no_such_var;

? is null	? is not null	?

1	0	NULL

set @var='abc';

select @var is null, @var is not null, @var;

@var is null	@var is not null	@var

0	1	abc

execute stmt using @var, @var, @var;

? is null	? is not null	?

0	1	abc

set @var=null;

select @var is null, @var is not null, @var;

@var is null	@var is not null	@var

1	0	NULL

execute stmt using @var, @var, @var;

? is null	? is not null	?

1	0	NULL

mysql-test/t/ps.test

+14 −0
Original line number Diff line number Diff line
@@ -458,3 +458,17 @@ EXECUTE stmt; 
DEALLOCATE PREPARE stmt;

DROP TABLE t1;



# 

# Bug#6297 "prepared statement, wrong handling of <parameter> IS NULL"

# Test that placeholders work with IS NULL/IS NOT NULL clauses. 

#

prepare stmt from "select ? is null, ? is not null, ?";

select @no_such_var is null, @no_such_var is not null, @no_such_var;

execute stmt using @no_such_var, @no_such_var, @no_such_var;

set @var='abc';

select @var is null, @var is not null, @var;

execute stmt using @var, @var, @var;

set @var=null;

select @var is null, @var is not null, @var;

execute stmt using @var, @var, @var;

sql/item.h

+10 −0
Original line number Diff line number Diff line
@@ -266,6 +266,14 @@ class Item { 
  virtual bool get_time(TIME *ltime);

  virtual bool get_date_result(TIME *ltime,uint fuzzydate)

  { return get_date(ltime,fuzzydate); }

  /*

    This function is used only in Item_func_isnull/Item_func_isnotnull

    (implementations of IS NULL/IS NOT NULL clauses). Item_func_is{not}null

    calls this method instead of one of val/result*() methods, which

    normally will set null_value. This allows to determine nullness of

    a complex expression without fully evaluating it.

    Any new item which can be NULL must implement this call.

  */

  virtual bool is_null() { return 0; }

  /*

    it is "top level" item of WHERE clause and we do not need correct NULL
@@ -573,6 +581,8 @@ class Item_param :public Item 
  void print(String *str) { str->append('?'); }

  /* parameter never equal to other parameter of other item */

  bool eq(const Item *item, bool binary_cmp) const { return 0; }

  bool is_null()

  { DBUG_ASSERT(state != NO_VALUE); return state == NULL_VALUE; }

};



class Item_int :public Item_num