sql - PostgreSQL: Aggregate by more than one column -

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i have following data format:

id       eventtime           use    2015-01-01 00:00:00-01    5.2 . .    2015-06-06 23:59:50-01    5.7   b  . .

i'm trying output of form:

id        eventtime              use         2015-01-01             1200 .         2015-06-06             1400   . b         2015-01-01             1500

basically sum of item use every user each day in database.

i tried

select id, eventtime, sum(use) table group id,eventtime

i got aggregate in case can't make sense of i.e doesn't add should. appreciated, in advance!

you need convert eventtime date removing time component. think simplest way using date_trunc():

select id, date_trunc('day', eventtime) eventday, sum(use) table group id, eventday order id, eventday;

i'm not sure why sample query has id in select, user in group by.


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