Re: [GENERAL] count case when - PG 9.2

On 2017-03-09 05:27, Patrick B wrote:

Hi guys. How can I count using 'CASE WHEN'?

Example:

SELECT

CASE

WHEN AND c.regdate > EXTRACT(epoch FROM (now() - INTERVAL
'14 day'))

THEN 'trial'

WHEN last_pay > EXTRACT(epoch FROM (now() - INTERVAL '37
day'))

THEN 'paying'

END as account_status,

c.id [1]

FROM public.clients c

WHERE (

(last_pay > EXTRACT('epoch' FROM now() - '12
Months'::INTERVAL))

)

ORDER BY 1

 I wanna know how many of 'trial' and 'paying' customers the query
returns. can you guys please advice how to do it?

Thanks
Patrick

comparisons like "A>B" return a boolean. Booleans can be cast to integers, and integers can be summed.

SUM((A>B)::int)

But depending on the situation, indexes etc it could be faster to run e separate count query, you'll have to test that.