Josep Sanmartí wrote:
> Hello,
> I have a 'big' problem:
> I have the following table users(name, start_time, end_time), a new row
> is set whenever a user logs into a server. I want to know how many
> users have logged in EVERYDAY between 2 different dates. The only idea
> that I have is making several select (one for each day):
> SELECT COUNT(name) FROM users WHERE start_time between "startDate"
> and "startDate+1"
> SELECT COUNT(name) FROM users WHERE start_time between "startDate+1"
> and "startDate+2"
> ...
> I would like to know if its possible to make it in 1 sql statement or
> just which is the best efficient way to solve it.
> By the way, I use Postgres 7.4.
>
> Thanks!
>
SELECT
date_trunc('day', start_time) as day, count(name)
FROM
users
WHERE
start_time between "startDate" AND "endDate"
GROUP BY
day;