3 table addition and subtraction

Question

I have three tables:

I want to group all the results according to Table 3 collection operation and year.

Here is an example of what I want:

tablo1
2017 -> 2100(alacak)

tablo2
2017 -> 600(borc)

• 2100(alacak) - 600(borc) = 1600(result)

tablo3
2017 -> 600(gider)

• 1600(result) - 600(gider) = 1000(final)

I tried a code like this:

SELECT tablo1.year, (SUM(tablo1.alacak)-SUM(tablo2.borc)-SUM(tablo3.gider)) AS result
FROM
    tablo1 JOIN tablo2 ON tablo1.alacak = tablo2.borc        
    LEFT JOIN giderler ON tablo1.alacak = tablo3.gider
    GROUP BY tablo1.year DESC;

But it doesn't work. Any help will be appreciated.

Answer 1

Is this what you want???

select year,
 (select sum(alacak) quantity 
      from table1 
    where table1.year = t3.year) 
    -
 (select sum(borc) quantity
    from table2 
   where table2.year = t3.year)
   - 
 (select sum(gider) quantity 
    from table3
   where table3.year = t3.year) as result
   from table3 t3
   group by year;