I have some table called classification that contains classification_indicator_id
.
I need to sum this ID
and put in 1 day series.
I need to add around 20 columns (with another classification_indicator_id
).
I modified a bit answer from previous question :
select
data.d::date as "data",
sum(c.classification_indicator_id)::integer as "Segment1",
sum(c4.classification_indicator_id)::integer as "Segment2",
sum(c5.classification_indicator_id)::integer as "Segment3"
from
generate_series(
'2013-03-25'::timestamp without time zone,
'2013-04-01'::timestamp without time zone,
'1 day'::interval
) data(d)
left join classifications c on (data.d::date = c.created::date and c.classification_indicator_id = 3)
left join classifications c4 on (data.d::date = c4.created::date and c4.classification_indicator_id = 4)
left join classifications c5 on (data.d::date = c5.created::date and c5.classification_indicator_id = 5)
group by "data"
ORDER BY "data"
But still not working properly. sum
for each row is to big, and growing when I add additional columns. In second table with 4 columns in segment1
for 2013-03-26 should be the same amount like in first table etc.
With 3 column With 4 columns
data | Segment1 | Segment2 data | Segment1 | Segment2 | Segment3
-------------------------------- -------------------------------------------
2013-03-25 | 12 | 16 2013-03-25 | 12 | 16 | 20
-------------------------------- -------------------------------------------
2013-03-26 | 18 | 24 2013-03-26 | 108 | 144 | 180
As commented under your previous answer , you are running into a "proxy cross join".
I explained it in more detail in this related answer:
Two SQL LEFT JOINS produce incorrect result
Your query should work like this:
SELECT d.created AS data
,c3.segment1
,c4.segment2
,c5.segment3
FROM (
SELECT generate_series('2013-03-25'::date
,'2013-04-01'::date
,interval '1 day')::date AS created
) d
LEFT JOIN (
SELECT created
,sum(classification_indicator_id)::integer AS segment1
FROM classifications
WHERE classification_indicator_id = 3
GROUP BY 1
) c3 USING (created)
LEFT JOIN (
SELECT created
,sum(classification_indicator_id)::integer AS segment2
FROM classifications
WHERE classification_indicator_id = 4
GROUP BY 1
) c4 USING (created)
LEFT JOIN (
SELECT created
,sum(classification_indicator_id)::integer AS segment3
FROM classifications
WHERE classification_indicator_id = 5
GROUP BY 1
) c5 USING (created)
ORDER BY 1;
Assuming that created
is a date
, not a timestamp
.
Or, for an even faster query, since this has become a topic:
SELECT d.created AS data
,count(classification_indicator_id = 3 OR NULL)::int * 3 AS segment1
,count(classification_indicator_id = 4 OR NULL)::int * 4 AS segment2
,count(classification_indicator_id = 5 OR NULL)::int * 5 AS segment3
FROM (
SELECT generate_series('2013-03-25'::date
,'2013-04-01'::date
,interval '1 day')::date AS created
) d
LEFT JOIN classifications c USING (created)
GROUP BY 1
ORDER BY 1;
No need for joins:
select
data.d::date as "data",
sum((classification_indicator_id = 3)::integer * classification_indicator_id)::integer as "Segment1",
sum((classification_indicator_id = 4)::integer * classification_indicator_id)::integer as "Segment2",
sum((classification_indicator_id = 5)::integer * classification_indicator_id)::integer as "Segment3",
from
generate_series(
'2013-03-25'::timestamp without time zone,
'2013-04-01'::timestamp without time zone,
'1 day'::interval
) data(d)
left join
classifications c on data.d::date = c.created::date
group by "data"
ORDER BY "data"
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