I have a CTE based query, to which I pass about 2600 4-tuple latitude/longitude values using joins – these latitude longitude 4-tuples have been ID tagged and held in a second table called coordinates. These top left and bottom right latitude / longitude values are passed into the CTE in order to display the amount of requests (hourly) made within those coordinates for given two timestamps).- I am able to get the total requests per day within the timestamps given, that is, the total count of user requests on every specified day. (E.g. user opts to see every Wednesday or Wednesday AND Thursday etc. – between hours 11:55 and 22:04 between dates January 1 and 31, 2012 for every latitude/longitude 4-tuples I pass.) But I cannot get the rows with zcount as 0 in the results, I only get the rows with zcount > 0. My query is as below: (a note to Erwin Brandstetter if he sees this, I checked the chat room discussion about my previous question and set the coordinates values to NOT NULL due to you saying that the coordinates can be null by design, but I still have the same issue somehow. -though I may have gotten what you meant wrong since I was down with a bad case of fever back then-
WITH v AS (
SELECT '2012-1-1 11:55:11'::timestamp AS _from -- provide times once
,'2012-1-31 22:02:21'::timestamp AS _to
)
, q AS (
SELECT c.coordinates_id
, date_trunc('hour', t.calltime) AS stamp
, count(*) AS zcount
FROM v
JOIN mytable t ON t.calltime BETWEEN v._from AND v._to
AND (t.calltime::time >= v._from::time AND
t.calltime::time <= v._to::time) AND
(extract(DOW from t.calltime) = 3)
JOIN coordinates c ON (t.lat, t.lon)
BETWEEN (c.bottomrightlat, c.topleftlon)
AND (c.topleftlat, c.bottomrightlon)
GROUP BY c.coordinates_id, date_trunc('hour', t.calltime)
)
, cal AS (
SELECT generate_series('2012-1-1 11:00:00'::timestamp
, '2012-1-31 23:00:00'::timestamp
, '1 hour'::interval) AS stamp)
SELECT q.coordinates_id, cal.stamp::date, sum(q.zcount) AS zcount
FROM v, cal
LEFT JOIN q USING (stamp)
WHERE extract(hour from cal.stamp) BETWEEN extract(hour from v._from)
AND extract(hour from v._to)
AND extract(DOW from cal.stamp) = 3
AND cal.stamp >= v._from
AND cal.stamp <= v._to
GROUP BY 1,2
ORDER BY 1,2;
The output I get when I execute this query is basically like this (normally I have about 10354 rows returned excluding the rows with 0 zcount, just providing two coordinates for sake of similarity):
coordinates_id | stamp | zcount
1 ;"2012-01-04"; 2
1 ;"2012-01-11"; 3
1 ;"2012-01-18"; 2
2 ;"2012-01-04"; 2
2 ;"2012-01-11"; 3
2 ;"2012-01-18"; 2
However, it should be like this where all rows with zcount 0 should also be printed out along with rows that have nonzero zcounts -E.g. January 25 with zcount 0 for the two coordinates with ID 1 and 2 should also be printed in this small portion of example-:
coordinates_id | stamp | zcount
1 ;"2012-01-04"; 2
1 ;"2012-01-11"; 3
1 ;"2012-01-18"; 2
1 ;"2012-01-25"; 0
2 ;"2012-01-04"; 2
2 ;"2012-01-11"; 3
2 ;"2012-01-18"; 2
2 ;"2012-01-25"; 0
Updated version with zcount values way bigger than actual. -Also rows with 0 zcount still not showing-
WITH v AS (
SELECT '2012-1-1 11:55:11'::timestamp AS _from -- provide times once
,'2012-1-31 22:02:21'::timestamp AS _to
)
, q AS (
SELECT c.coordinates_id
, date_trunc('hour', t.calltime) AS stamp
, count(*) AS zcount
FROM v
JOIN mytable t ON t.calltime BETWEEN v._from AND v._to
AND (t.calltime::time >= v._from::time AND
t.calltime::time <= v._to::time) AND
(extract(DOW from t.calltime) = 3)
JOIN coordinates c ON (t.lat, t.lon)
BETWEEN (c.bottomrightlat, c.topleftlon)
AND (c.topleftlat, c.bottomrightlon)
GROUP BY c.coordinates_id, date_trunc('hour', t.calltime)
)
, cal AS (
SELECT generate_series('2012-1-1 11:00:00'::timestamp
, '2012-1-31 23:00:00'::timestamp
, '1 hour'::interval) AS stamp)
, coordst AS (
SELECT coordinates_id FROM coordinates)
SELECT q.coordinates_id, cal.stamp::date, COALESCE(sum(q.zcount),0) AS zcount
FROM v, coordst, cal
LEFT JOIN q USING (stamp)
WHERE extract(hour from cal.stamp) BETWEEN extract(hour from v._from)
AND extract(hour from v._to)
AND extract(DOW from cal.stamp) = 3
AND cal.stamp >= v._from
AND cal.stamp <= v._to
GROUP BY 1,2
ORDER BY 1,2;
You need a distinct list of coordinates_id to perform a proper CROSS JOIN.
1. Add another entry in the WITH.
2. Add it to your JOIN (FROM v,cal, coords).
3. Your zcount will show NULL, so COALESCE it.