Issue with group by and order by clause with inner join - php

Question

I have two tables namely locations and pilots. I have been trying to fetch data based on location_id i.e selecting pilots who are flying in a particular location_id order by date(date of schedule).
I am using group by as i need only distinct pilots to be displayed.
select B.*,
A.rather_to_be_flying_now,
A.here_now,
A.flying,
A.when,
A.my_favorite,
A.start,
A.end,
A.Locationid
from locations A
inner join pilots B
on A.Pilotid=B.pilot_id
where A.VenueID='$venueid'
and (A.flying='1' or A.here_now='1')
group by A.Pilotid
ORDER BY A.start
The query works good if i wont include a group by clause. It returns the following result
with out group by clause
with group by clause
But the above table shows wrong order, as the output must return start time as 2013-01-24 02:00:00 for pilotid 1 (Chronological order).

Answer 1

You can use MIN()
select B.*,
A.rather_to_be_flying_now,
A.here_now,
A.flying,
A.when,
A.my_favorite,
MIN(A.start) as start,
A.end,
A.Locationid
from locations A
inner join pilots B
on A.Pilotid=B.pilot_id
where A.VenueID='$venueid'
and (A.flying='1' or A.here_now='1')
group by A.Pilotid
ORDER BY A.start

Answer 2

Try this instead:
SELECT
B.*,
A.rather_to_be_flying_now,
A.here_now,
A.flying,
A.when,
A.my_favorite,
A.start,
A.end,
A.Locationid
FROM locations A
INNER JOIN
(
SELECT pilotid, MIN(start) MinStart
FROM locations
GROUP BY pilotid
) a2 ON A.pilotId = a2.pilotId
AND a.start = a2.minStart
INNER JOIN pilots B on A.Pilotid = B.pilot_id
WHERE A.VenueID = '$venueid'
AND (A.flying='1' OR A.here_now='1');
ORDER BY A.start ;
This will give you only those pilots with the minimum start date.

Answer 3

Try this query -
SELECT
p.pilit_id, l.location_id, l.start
FROM pilots p
JOIN (SELECT l1.*
FROM locations l1
JOIN (SELECT location_id, MIN(start) start
FROM locations
GROUP BY locations) l2
ON l1.id = l2.id AND l1.start = l2.start
) l
ON l.pilot_id = p.pilot_id
GROUP BY p.pilot_id
Add your WHERE condition.