Deal with properly

mysql-test/suite/oqgraph/isnull.result

+DROP TABLE IF EXISTS graph_base;
+DROP TABLE IF EXISTS graph;
+DROP TABLE IF EXISTS graph2;
+CREATE TABLE graph_base (
+from_id INT UNSIGNED NOT NULL,
+to_id INT UNSIGNED NOT NULL,
+PRIMARY KEY (from_id,to_id),
+INDEX (to_id)
+) ENGINE=MyISAM;
+CREATE TABLE graph (
+latch   VARCHAR(32) NULL,
+origid  BIGINT    UNSIGNED NULL,
+destid  BIGINT    UNSIGNED NULL,
+weight  DOUBLE    NULL,
+seq     BIGINT    UNSIGNED NULL,
+linkid  BIGINT    UNSIGNED NULL,
+KEY (latch, origid, destid) USING HASH,
+KEY (latch, destid, origid) USING HASH
+) ENGINE=OQGRAPH DATA_TABLE='graph_base' ORIGID='from_id', DESTID='to_id';
+INSERT INTO graph_base(from_id, to_id) VALUES (1,2), (2,1);
+INSERT INTO graph_base(from_id, to_id) VALUES (1,3), (3,1);
+INSERT INTO graph_base(from_id, to_id) VALUES (3,4), (4,3);
+INSERT INTO graph_base(from_id, to_id) VALUES (5,6), (6,5);
+select * from graph where latch is null;
+latch	origid	destid	weight	seq	linkid
+NULL	1	2	1	NULL	NULL
+NULL	2	1	1	NULL	NULL
+NULL	1	3	1	NULL	NULL
+NULL	3	1	1	NULL	NULL
+NULL	3	4	1	NULL	NULL
+NULL	4	3	1	NULL	NULL
+NULL	5	6	1	NULL	NULL
+NULL	6	5	1	NULL	NULL
+select * from graph where latch is null and origid=1;
+latch	origid	destid	weight	seq	linkid
+NULL	1	NULL	1	2	3
+NULL	1	NULL	1	1	2
+select * from graph where latch is null and destid=2;
+latch	origid	destid	weight	seq	linkid
+NULL	NULL	2	1	1	1
+DROP TABLE graph_base;
+DROP TABLE graph;

mysql-test/suite/oqgraph/isnull.test

@@ -31,6 +31,8 @@ INSERT INTO graph_base(from_id, to_id) VALUES (3,4), (4,3);
 INSERT INTO graph_base(from_id, to_id) VALUES (5,6), (6,5);
 
 select * from graph where latch is null;
+select * from graph where latch is null and origid=1;
+select * from graph where latch is null and destid=2;
 
 DROP TABLE graph_base;
 DROP TABLE graph;