将一个sql列基于两个列求和，将另一个表与条件求和

Question

Table teststock :

type date   time product qty
in  26-Apr  6.5 vs29    10
out 26-Apr  5.4 vs29    2
in  26-Apr  8.9 vs29    5
out 25-Apr  7.2 vs29    10
in  27-Apr  5.2 vs29    5

Table product list :

id  product inward  outward stock
1   vs29    20      12      8

I need sql statements for asp.net.

1. sum the inward in product list from qty based on type in
2. sum the outward in product list from qty based on type out
3. finally subtract inward-outward

Answer 1

I don't know exactly what you want, but I think you want to do something like this :

select a.product , sum(a.inward) inward ,sum(a.outward) outward , sum(a.inward) - sum(a.outward) stock   from (
select product , case when type = 'in' then qty else 0 end inward , 
case when type = 'out' then qty else 0 end outward
from test_stock) a
group by a.product

This is sqlfiddle link about sql query : http://sqlfiddle.com/#!6/65f06e/5