Calculating difference of dates In Postgresql

Question

I\'m trying to find out the time between certain fields in my tables. However cause I\'m using Postgresql :(( I can\'t use the DATEDIFF function. I can\'t f

Answer 1

You can use the age(<date1>, <date2>) function (instead of DATEDIFF).

This should work -

SELECT Question.ID, 
Question.Status, COUNT (qUpdate.ID)  AS NumberofUpdates,
age(Question.LoggedTime,MIN(qUpdate.UpdateTime)) AS TimeBeforeFirstUpdate,
age(Question.LoggedTime, MAX(qUpdate.UpdateTime)) AS TimeBeforeLastUpdate
FROM qUpdate
LEFT JOIN Question ON qUpdate.qID=Question.ID
WHERE Question.Status = 'closed' AND qUpdate.Update NOT NULL
GROUP BY Question.Status, Question.ID, Question.LoggedTime;

Note, if psql gives you this error - ERROR: date/time field value out of range, then you would need to choose an appropriate datestyle.

Answer 2

SELECT extract(year from age('2014-01-23', '1985-08-27'));
-- returns 28 years, my current age.

Answer 3

You don't need a "datediff" function.

Just subtract the two dates:

Question.LoggedTime - MIN(qUpdate.UpdateTime)

In case you don't know, but all that is documented online:
http://www.postgresql.org/docs/current/static/functions-datetime.html