Ali Madadi Ali Madadi - 3 months ago 11x
SQL Question

subtract two column from different table and group by

after one week search i couldn't write this query please help me.
i have 3 table purchase, selles, stuff.
i want to first sum purchase.quantity selles.quantity fields separately and then subtract these two column purchase.quantity selles.quantity then GROUP BY purchase.scale,

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i have these 3 table

table purchase:
'id', 'invoice_id', 'stuff_id', 'quantity', 'scale', 'price'
table selles:
'id', 'selles_invoice_num', 'stuff_id', 'quantity', 'scale', 'price'
table stuff:
'id', 'name'

i have this query but result (quantities) is wrong

SELECT sum(purchase.quantity) - sum(selles.quantity) as quantities,
purchase.scale, ,
FROM purchase,
where purchase.stuff_id = selles.stuff_id
and purchase.scale = selles.scale
and purchase.stuff_id =
group by purchase.scale,

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Try with inner join

        SELECT sum(pur.psum) - sum(sca.ssum) as quantities, p.scale, , FROM
 stuff st INNER JOIN  
    (SELECT sum(p.quantity) as psum,p.scale,p.stuff_id  FROM purchase p GROUP BY p.scale,p.stuff_id) pur 
on pur.stuff_id =  INNER JOIN 
    (SELECT sum(s.quantity) as ssum,s.scale,s.stuff_id  FROM scale s GROUP BY s.scale,s.stuff_id) sca
 on sca.scale=pur.scale and sca.stuff_id=pur.stuff_id  group by pur.scale, ORDER BY , pur.scale;