sql subtraction on two different tables - sql

Question

I have two different tables, common column is truck_id.
I need to subtract two tables from each other to find the net amount.
The result I want:
truck_id
difference
35kd85
1500
35hh52
900
SELECT
(SELECT SUM(last_revenue) FROM (
SELECT DISTINCT last_revenue FROM
Expedition WHERE YEAR(departure_date) > 2020 AND truck_id = '31adc444'
UNION ALL SELECT last_revenue FROM
ChainingExpedition WHERE YEAR(departure_date) > 2020 AND truck_id = '31adc444'
)x
)-(SELECT SUM(price_dollar) FROM (
SELECT DISTINCT price_dollar FROM TruckMaintenanceExpense
WHERE YEAR(payment_date) > 2020 AND expense_type = 'çeker'
AND truck_id ='31adc444'
)x
) AS difference
SQL subtraction on two different tables
When I type truck_id in my query, I get the right result, but my goal is to draw as a list.

Answer 1

Typically, I would create a list of all trucks that meet the criteria you are looking for. Then, I'll get a list of all trucks with revenue and a separate list of trucks with expense. Then you join those 3 tables together and do the math. You query was very hard to follow without good indenting and structure. Next time you ask a question, be sure to include sample data. You should be writing all the CREATE TABLE and INSERT INTO statements that I include in the EXAMPLE DATA section in the fiddle below.
--*****EXAMPLE DATA*****
CREATE TABLE Expedition (
truck_id nvarchar(50)
, last_revenue decimal(19,2)
, departure_date datetime
);
CREATE TABLE TruckMaintenanceExpense (
truck_id nvarchar(50)
, price_dollar decimal(19,2)
, payment_date datetime
);
INSERT INTO Expedition (truck_id, last_revenue, departure_date)
VALUES ('35kd85', 2000.00, '2020-1-1')
, ('35kd85', 3500.00, '2020-1-1')
, ('35hh52', 300.00, '2020-1-1')
, ('35hh52', 258.98, '2020-1-1')
;
INSERT INTO TruckMaintenanceExpense (truck_id, price_dollar, payment_date)
VALUES ('35kd85', 9865.23, '2020-2-1')
, ('35kd85', 321.54, '2020-2-1')
, ('35hh52', 159.78, '2020-2-1')
, ('35hh52', 598.77, '2020-2-1')
;
--*****END EXAMPLE DATA*****
--Create a list of all truck_ids. It would be more helpful
--if you had a table that defined all the trucks (i.e. dbo.trucks).
WITH AllTrucks as (
SELECT truck_id
FROM TruckMaintenanceExpense
UNION ALL
SELECT truck_id
FROM Expedition
)
SELECT DISTINCT
a.truck_id
--Use ISNULL to make sure we have 0.00 if the truck is missing
--either revenue or expense.
, ISNULL(tRev.total_revenue,0) - ISNULL(tExp.total_expense,0) as difference
--Get the list of truck_ids. Use SELECT DISTINCT to elimiate duplicates.
FROM AllTrucks as a
--Get a list of all trucks with Expedition reveue.
LEFT OUTER JOIN (
SELECT
e.truck_id
, YEAR(e.departure_date) as [year]
, SUM(e.last_revenue) as total_revenue
FROM Expedition as e
WHERE e.departure_date >= '2020-1-1 00:00:00'
AND e.departure_date < '2021-1-1 00:00:00'
GROUP BY e.truck_id, YEAR(departure_date)
) as tRev
ON tRev.truck_id = a.truck_id
--Get a list of all trucks with maintenance expenses.
LEFT OUTER JOIN (
SELECT
tme.truck_id
, YEAR(tme.payment_date) as [year]
, SUM(tme.price_dollar) as total_expense
FROM TruckMaintenanceExpense as tme
WHERE tme.payment_date >= '2020-1-1 00:00:00'
AND tme.payment_date < '2021-1-1 00:00:00'
GROUP BY tme.truck_id, YEAR(payment_date)
) as tExp
ON tExp.truck_id = a.truck_id
;
truck_id
difference
35hh52
-199.57
35kd85
-4686.77
fiddle