在SQL中选择多个变量

Question

So I have the following problem.

I have a receipts table with several columns, among others I have 2 columns 'receipt_id' and other 'status' .

'Status' can take the following values: 'active' and 'unpaid' .

I would like to run a query to have an output of the following ratio (lets call it 'RR') RR=active/(active+unpaid)

I've tried to make 'RR' as a variable and then input the arguments with their conditions using 'AS' function.

Also I've tried to make the following:

select count(distinct r.user_id) from receipts as r where r.status='active' as active, count(distinct r.user_id) from receipts as r where r.status='unpaid' as unpaid

(in order to get two different columns and the make the ratio 'RR' with a simple formula).

None of this is working...

Could someone please help me? Thanks in advance

Answer 1

Just use conditional aggregation. I think this is the simplest method:

select avg(r.status = 'active')
from receipts r
where r.status in ('active', 'unpaid');