Combining Two Queries and Calculating Result - postgresql

Question

I am attempting to calculate the difference between query 1:
select case
when cnt >= 1 AND cnt <= 2000 then cnt * 6
when cnt >= 2001 AND cnt <= 4000 then ((cnt - 2000) * 5) + 12000
when cnt >= 4001 AND cnt <= 6000 then ((cnt - 4000) * 4) + 22000
when cnt >= 6001 AND cnt <= 8000 then ((cnt - 6000) * 3) + 30000
when cnt >= 8001 then ((cnt - 8000) * 2) + 36000
else 1
end "Customer Investment"
from (
select COUNT(*) as cnt
from "mv_fundraiser_report"
where thank_you_delivered = true
[[AND {{NonProfit}}]]
[[AND {{StartDate}}]]
) t
And Query 2:
SELECT ((cast(A.TNUM as float)/cast(A.TDENOM as float))-(cast(A.FNUM as float)/cast(A.FDENOM as float)))*cast(A.TDENOM as float) AS "Heck"
FROM (SELECT
(SELECT SUM("public"."mv_fundraiser_report"."total_raised")
FROM "public"."mv_fundraiser_report"
WHERE ("public"."mv_fundraiser_report"."opt-in" = FALSE
AND NOT "public"."mv_fundraiser_report"."campaign_id" = 704943916598630
AND NOT "public"."mv_fundraiser_report"."campaign_id" = 193572775319413
AND NOT(first_name IS NULL
AND total_raised > 1000
AND fundraiser_type = 'Generic Fundraiser')
AND [[{{NonProfit}}]]
AND [[{{DateRange}}]])) AS FNUM,
(SELECT count(*) AS "count"
FROM "public"."mv_fundraiser_report"
WHERE ("public"."mv_fundraiser_report"."opt-in" = FALSE
AND NOT "public"."mv_fundraiser_report"."campaign_id" = 704943916598630
AND NOT "public"."mv_fundraiser_report"."campaign_id" = 193572775319413
AND NOT(first_name IS NULL
AND total_raised > 1000
AND fundraiser_type = 'Generic Fundraiser')
AND [[{{NonProfit}}]]
AND [[{{DateRange}}]])) AS FDENOM,
(SELECT SUM("public"."mv_fundraiser_report"."total_raised")
FROM "public"."mv_fundraiser_report"
WHERE ("public"."mv_fundraiser_report"."opt-in" = TRUE
AND NOT "public"."mv_fundraiser_report"."campaign_id" = 704943916598630
AND NOT "public"."mv_fundraiser_report"."campaign_id" = 193572775319413
AND NOT(first_name IS NULL
AND total_raised > 1000
AND fundraiser_type = 'Generic Fundraiser')
AND [[{{NonProfit}}]]
AND [[{{DateRange}}]])) AS TNUM,
(SELECT count(*) AS "count"
FROM "public"."mv_fundraiser_report"
WHERE ("public"."mv_fundraiser_report"."opt-in" = TRUE
AND NOT "public"."mv_fundraiser_report"."campaign_id" = 704943916598630
AND NOT "public"."mv_fundraiser_report"."campaign_id" = 193572775319413
AND NOT(first_name IS NULL
AND total_raised > 1000
AND fundraiser_type = 'Generic Fundraiser')
AND [[{{NonProfit}}]]
AND [[{{DateRange}}]])) AS TDENOM) A
Both of the queries work by themselves and return a single number, but I am struggling heavily with the syntax. I'm totally unsure of how I can make use of (window?) functions in order to achieve my end result. Any help is appreciated, thanks!

Answer 1

You can place each query into common table expressions, then subtract one from the other.
For example (reworked query 2 for simplification):
WITH one AS (
SELECT
CASE
WHEN cnt >= 1 AND cnt <= 2000 THEN cnt * 6
WHEN cnt >= 2001 AND cnt <= 4000 THEN ((cnt - 2000) * 5) + 12000
WHEN cnt >= 4001 AND cnt <= 6000 THEN ((cnt - 4000) * 4) + 22000
WHEN cnt >= 6001 AND cnt <= 8000 THEN ((cnt - 6000) * 3) + 30000
WHEN cnt >= 8001 THEN ((cnt - 8000) * 2) + 36000
ELSE 1
END "Customer Investment"
FROM (
SELECT COUNT(*) as cnt
FROM "mv_fundraiser_report"
WHERE thank_you_delivered = true
[[AND {{NonProfit}}]]
[[AND {{StartDate}}]]
) t
),
two AS (
SELECT (
(
SUM(public.mv_fundraiser_report.total_raised)
FILTER (WHERE public.mv_fundraiser_report.opt-in = FALSE)
)::float AS FNUM /
(
count(*)
FILTER (WHERE public.mv_fundraiser_report.opt-in = FALSE)
)::float AS FDENOM
) -
(
(
SUM(public.mv_fundraiser_report.total_raised)
FILTER (WHERE public.mv_fundraiser_report.opt-in = TRUE)
)::float AS TNUM /
(
count(*)
FILTER (WHERE public.mv_fundraiser_report.opt-in = TRUE)
)::float AS TDENOM
) AS "Heck"
FROM public.mv_fundraiser_report
WHERE NOT public.mv_fundraiser_report.campaign_id = 704943916598630
AND NOT public.mv_fundraiser_report.campaign_id = 193572775319413
AND NOT (first_name IS NULL
AND total_raised > 1000
AND fundraiser_type = 'Generic Fundraiser')
AND [[{{NonProfit}}]]
AND [[{{DateRange}}]])
)
SELECT one."Customer Investment" - two."Heck" AS difference
FROM one, two;
I don't have your data or schema to test this against, so this untested.