Question

Is it possible to write a PostgreSQL query that gives time differences based on other record data?

That is, I have something like:

ID | CAT | Realtime   | Value   
---+-----+------------+------
A  |   1 | timestamp1 |    10
A  |   1 | timestamp2 |    15
A  |   2 | timestamp1 |     2
A  |   2 | timestamp2 |    55
B  |   1 | timestamp1 |     5
B  |   1 | timestamp2 |    10

And I’d like to add a field that finds the difference between timestamp 2 – timestamp1 based on identifiers ID AND CAT.

Answer 1

I’m not entirely sure what you’re asking, but is this what you’re looking for?

select id,cat,max(realtime)-min(realtime) as interval
from table
group by 1,2;