bk commit into 4.1 tree (igor:1.2292) BUG#11142

[igor]

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ChangeSet
  1.2292 05/06/13 11:24:26 igor@stripped +3 -0
  func_if.result, func_if.test:
    Added a test case for bug #11142.
  item_cmpfunc.cc:
    Fixed bug #11142.
    Implementation of Item_func_nullif::is_null was corrected.

  mysql-test/r/func_if.result
    1.14 05/06/13 11:23:55 igor@stripped +27 -0
    Added a test case for bug #11142.

  mysql-test/t/func_if.test
    1.11 05/06/13 11:23:22 igor@stripped +27 -0
    Added a test case for bug #11142.

  sql/item_cmpfunc.cc
    1.190 05/06/13 11:21:35 igor@stripped +1 -3
    Fixed bug #11142.
    Implementation of Item_func_nullif::is_null was corrected.

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	igor
# Host:	igor-inspiron.creware.com
# Root:	/home/igor/dev/mysql-4.1-0

--- 1.189/sql/item_cmpfunc.cc	Sun Jun  5 10:38:40 2005
+++ 1.190/sql/item_cmpfunc.cc	Mon Jun 13 11:21:35 2005
@@ -1161,9 +1161,7 @@
 bool
 Item_func_nullif::is_null()
 {
-  if (!cmp.compare())
-    return (null_value=1);
-  return 0;
+  return (null_value= (!cmp.compare() ? 1 : args[0]->null_value)); 
 }
 
 /*

--- 1.13/mysql-test/r/func_if.result	Wed Oct  6 05:09:39 2004
+++ 1.14/mysql-test/r/func_if.result	Mon Jun 13 11:23:55 2005
@@ -86,3 +86,30 @@
 SELECT NULLIF(5,5) IS NULL, NULLIF(5,5) IS NOT NULL;
 NULLIF(5,5) IS NULL	NULLIF(5,5) IS NOT NULL
 1	0
+DROP TABLE IF EXISTS t1;
+CREATE TABLE t1 (a CHAR(10));
+INSERT INTO t1 VALUES ('aaa'), (NULL), (''), ('bbb');
+SELECT a, NULLIF(a,'') FROM t1;
+a	NULLIF(a,'')
+aaa	aaa
+NULL	NULL
+	NULL
+bbb	bbb
+SELECT a, NULLIF(a,'') FROM t1 WHERE NULLIF(a,'') IS NULL;
+a	NULLIF(a,'')
+NULL	NULL
+	NULL
+DROP TABLE t1;
+CREATE TABLE t1 (a CHAR(10));
+INSERT INTO t1 VALUES ('aaa'), (NULL), (''), ('bbb');
+SELECT a, NULLIF(a,'') FROM t1;
+a	NULLIF(a,'')
+aaa	aaa
+NULL	NULL
+	NULL
+bbb	bbb
+SELECT a, NULLIF(a,'') FROM t1 WHERE NULLIF(a,'') IS NULL;
+a	NULLIF(a,'')
+NULL	NULL
+	NULL
+DROP TABLE t1;

--- 1.10/mysql-test/t/func_if.test	Wed Oct  6 09:14:30 2004
+++ 1.11/mysql-test/t/func_if.test	Mon Jun 13 11:23:22 2005
@@ -60,3 +60,30 @@
 # Bug #5595  NULLIF() IS NULL returns false if NULLIF() returns NULL
 #
 SELECT NULLIF(5,5) IS NULL, NULLIF(5,5) IS NOT NULL;
+#
+# Test to check evaluation of MULLIF when the first argument is NULL
+# (motivated by the Bug 11142)
+#
+
+--disable_warnings
+DROP TABLE IF EXISTS t1;
+--enable_warnings
+
+CREATE TABLE t1 (a CHAR(10));
+INSERT INTO t1 VALUES ('aaa'), (NULL), (''), ('bbb');
+SELECT a, NULLIF(a,'') FROM t1;
+SELECT a, NULLIF(a,'') FROM t1 WHERE NULLIF(a,'') IS NULL;
+
+DROP TABLE t1;
+
+#
+# Test for bug #11142: evaluation of NULLIF when the first argument is NULL
+#
+
+CREATE TABLE t1 (a CHAR(10));
+INSERT INTO t1 VALUES ('aaa'), (NULL), (''), ('bbb');
+
+SELECT a, NULLIF(a,'') FROM t1;
+SELECT a, NULLIF(a,'') FROM t1 WHERE NULLIF(a,'') IS NULL;
+
+DROP TABLE t1;