यह क्वेरी हमेशा कम से कम 1 पंक्ति लौटाती है
SELECT * FROM (__your old query__)aaa
UNION
SELECT NULL as research_cost, NULL as tech_name, NULL as research_prev,
... etc [FROM DUAL] // DUAL is a dummy table in mysql
यह क्वेरी हमेशा कम से कम 1 पंक्ति लौटाती है
SELECT * FROM (__your old query__)aaa
UNION
SELECT NULL as research_cost, NULL as tech_name, NULL as research_prev,
... etc [FROM DUAL] // DUAL is a dummy table in mysql