can we use two sum fuction in same query in Postgres - sql

Question

I written a query as mentioned below :
select
sum(co.BOMParentQty) as hiredqty,
cy.dehireqty as dehire,
cy.M_product_id,
co.Project_Prod
from c_order co
inner join M_CycleDays cy ON (co.Project_Prod :: numeric = cy.M_product_id)
where co.c_doctype_id = 1000600
AND co.Project_Prod = '1000470'
group by cy.M_product_id, co.Project_Prod, dehire
it gives me output for two lines but i want only single line with the sum of dehireqty if i put sum function for dehire qty column then it sums two times
Actual Output without Sum of dehireqty column is (two records):
6.00;2.00;1000470;"1000470"
6.00;3.00;1000470;"1000470"
After put sum function for dehireqty column:
12.00;15.00;1000470;"1000470"
But actually I want:
6.00;5.00;1000470;"1000470"
How can I get this result?

Answer 1

Just make your query a sub-query and sum-up dehireqty in outer-query:
SELECT
hiredqty,
SUM(dehire) AS dehireqty,
M_product_id,
Project_Prod
FROM (
select
sum(co.BOMParentQty) as hiredqty,
cy.dehireqty as dehire,
cy.M_product_id,
co.Project_Prod
from c_order co
inner join M_CycleDays cy ON (co.Project_Prod :: numeric = cy.M_product_id)
where co.c_doctype_id = 1000600
AND co.Project_Prod = '1000470'
group by cy.M_product_id, co.Project_Prod, dehire
) AS subquery Group by hiredqty,M_product_id,Project_Prod;