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, 19 insertions, 0 deletions

diff --git a/mysql-test/r/having.result b/mysql-test/r/having.result
index df99f2545cb..a33ce457176 100644
--- a/mysql-test/r/having.result
+++ b/mysql-test/r/having.result
@@ -44,3 +44,22 @@ AND start <= 999660;
 id	start	end	chr_strand
 133197	813898	813898	-1.0000
 drop table t1,t2;
+CREATE TABLE t1 (Fld1 int(11) default NULL,Fld2 int(11) default NULL);
+INSERT INTO t1 VALUES (1,10),(1,20),(2,NULL),(2,NULL),(3,50);
+select Fld1, max(Fld2) as q from t1 group by Fld1 having q is not null;
+Fld1	q
+1	20
+3	50
+select Fld1, max(Fld2) from t1 group by Fld1 having max(Fld2) is not null;
+Fld1	max(Fld2)
+1	20
+3	50
+select Fld1, max(Fld2) from t1 group by Fld1 having avg(Fld2) is not null;
+Fld1	max(Fld2)
+1	20
+3	50
+select Fld1, max(Fld2) from t1 group by Fld1 having std(Fld2) is not null;
+Fld1	max(Fld2)
+1	20
+3	50
+drop table t1;