Fix sorting of NULL values (Should always be first)

Fix problem with HAVING and MAX() IS NOT NULL


Docs/manual.texi:
  Changelog & NULL usage with ORDER BY
client/mysqldump.c:
  Cleanup disable keys
mysql-test/r/distinct.result:
  Fix results after ORDER BY with NULL fix
mysql-test/r/group_by.result:
  Fix results after ORDER BY with NULL fix
mysql-test/r/having.result:
  Testcase for bug with HAVING
mysql-test/t/distinct.test:
  Test for DISTINCT + ORDER BY DESC bug
mysql-test/t/having.test:
  Test of HAVING and MAX IS NOT NULL
sql/filesort.cc:
  Fix sorting of NULL values (Should always be first)
sql/item.h:
  Fix problem with HAVING and MAX() IS NOT NULL
sql/item_sum.h:
  Fix problem with HAVING and MAX() IS NOT NULL
sql/opt_range.cc:
  Fix problem with HAVING and MAX() IS NOT NULL
sql/opt_range.h:
  Fix sorting of NULL values
sql/sql_select.cc:
  Fix sorting of ORDER BY ... DESC on NULL values.

1 files changed, 11 insertions, 0 deletions

diff --git a/mysql-test/t/distinct.test b/mysql-test/t/distinct.test
index bf8a03ac40d..b850ec5d562 100644
--- a/mysql-test/t/distinct.test
+++ b/mysql-test/t/distinct.test
@@ -207,3 +207,14 @@ insert into t1 (a) values (1),(2),(3),(4),(1),(2),(3),(4);
 select distinct a from t1 group by b,a having a > 2 order by a desc;
 select distinct a,c from t1 group by b,c,a having a > 2 order by a desc;
 drop table t1;
+
+#
+# Test problem with DISTINCT and ORDER BY DESC
+#
+
+create table t1 (a char(1), key(a)) type=myisam;
+insert into t1 values('1'),('1');
+select * from t1 where a >= '1'; 
+select distinct a from t1 order by a desc;
+select distinct a from t1 where a >= '1' order by a desc;
+drop table t1;