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Postgresql select different values from the same column

Posted on 2014-04-15
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Last Modified: 2014-04-15
Hopefully a simple question, but I am stuck

I need to select and display in separate columns the number of true and false counts from a single table column e.g.

request    Date            delivered
1              01/04/14     t
2              01/04/14     f
3              01/04/14     f
4              02/04/14     f
5              02/04/14     t
6              03/04/14     f
etc...

right now I can only do something like this:

SELECT
date_part(d, date) AS day,
count(request) AS requests,
delivered
FROM table
WHERE date > '2014-03-31 23:59:59'
and delivered = true
GROUP BY 1, delivered
ORDER BY 1

but I want to have a result that looks like this

date          delivered =t    delivered=f
01/04/14  1                      2
02/04/14  1                      1
03/04/14  0                      1

Can anyone help?
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Question by:eezar21
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7 Comments
 
LVL 142

Expert Comment

by:Guy Hengel [angelIII / a3]
ID: 40001077
this is the basic code:
select date
, sum(case when delivered='t' then 1 else 0 end) t
, sum(case when delivered='f' then 1 else 0 end) f
from yourtable
group by date
order by date

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LVL 39

Expert Comment

by:Pratima Pharande
ID: 40001080
Select Date ,

Sum ( Case when delivered = 't' then 1 else 0 end) as T,
Sum ( Case when delivered = 'f' then 1 else 0 end) as F


From table
Group by Date
0
 
LVL 39

Expert Comment

by:Pratima Pharande
ID: 40001081
Sorry AngelIII , have not refreshed the page
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Author Comment

by:eezar21
ID: 40001153
Thanks guys but this gives me 2 different date lines for each date, rather than just one?
0
 
LVL 142

Accepted Solution

by:
Guy Hengel [angelIII / a3] earned 153 total points
ID: 40001161
only if the date field actually has date AND time, and you display only date part ...
see this article (though not targeted for postgresql):
http://www.experts-exchange.com/Database/Miscellaneous/A_1499-DATE-and-TIME-don%27t-be-scared-and-do-it-right-the-first-time.html

for your sql, you will need to extract/cast to only date, then the group by will work, for example date_trunc() function will do:
http://www.postgresql.org/docs/9.1/static/functions-datetime.html
select date_trunc('day', date)
, sum(case when delivered='t' then 1 else 0 end) t
, sum(case when delivered='f' then 1 else 0 end) f
from yourtable
group by date_trunc('day', date)
order by date_trunc('day', date) 

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0
 
LVL 39

Assisted Solution

by:Pratima Pharande
Pratima Pharande earned 152 total points
ID: 40001169
Select Date::timestamp::date ,

Sum ( Case when delivered = 't' then 1 else 0 end) as T,
Sum ( Case when delivered = 'f' then 1 else 0 end) as F


From table
Group by Date::timestamp::date

refer
http://stackoverflow.com/questions/6133107/extract-date-yyyy-mm-dd-from-a-timestamp-in-postgresql
0
 

Author Closing Comment

by:eezar21
ID: 40001299
Thanks for helping me through this - works perfectly and taught me some new query skills!
0

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