Pulling cost field from a sub-query - sql

Question

I wrote the following query to pull a unit cost from another table COSreport into my profitability query ProfitabilityReport and am having a problem with my sub-query.
select
i.tranid
, it.item_id
, it.displayname
, tl.Item_Count * -1 Unit_Qty
, case when tl.Item_Count=0 then 0
else ((tl.GROSS_AMOUNT * -1)/ Item_Count) * -1
end as PricePerUnit,
**(select sum(c.tranamt) from ns.COSreport c
inner join ns.ProfitabilityReport d
on c.InvoiceID = d.tranid
and c.item_id = d.item_id) as 'True Cost'**
, '0' 'Cost Per M'
from ns.tinvoice i
join ns.transaction_lines tl on i.transaction_id = tl.transaction_id
join ns.Customers cust on c.customer_id = i.ENTITY_ID
join ns.items it on it.item_id = tl.item_id
left join ns.ITEM_CLASSIFICATION it_class on it_class.list_id =
it.ITEM_CLASSIFICATION_ID
where list_item_name IS NOT NULL
and i.tranid = '1262INV'
I'm joining on both the invoice id and item id so that the proper cost is pulled across for the given invoice and item from COSReport.
However, the true cost is not coming up with the unit cost but instead is summing up the cost field for the entire table.
See below for example using invoice # 1262INV specified in the query above. The cost should be 1.04, .26, and 4 respectively vs 138m.
Any help getting this cleared up would be appreciated

Answer 1

I actually prefer using CTEs for readability. You can take your subquery, put it into a CTE, and then join it in your main query, but you'll want to add the tranid and item_id fields to the CTE so you can use them in your join.
EDIT: since you're using Azure SQL Server, you don't need the semicolon before the WITH.
WITH TrueCosts AS
(
SELECT
d.tranid
,d.item_id
,TrueCost = SUM(c.tranamt)
FROM ns.COSreport c
INNER JOIN ns.ProfitabilityReport d
ON c.InvoiceID = d.tranid
AND c.item_id = d.item_id
GROUP BY d.tranid
,d.item_id
)
SELECT
i.tranid
, it.item_id
, it.displayname
, tl.Item_Count * -1 Unit_Qty
, case when tl.Item_Count=0 then 0
else ((tl.GROSS_AMOUNT * -1)/ Item_Count) * -1
END as PricePerUnit
, tc.TrueCost AS 'True Cost'
, '0' AS 'Cost Per M'
FROM ns.tinvoice i
JOIN ns.transaction_lines tl on i.transaction_id = tl.transaction_id
JOIN ns.Customers c on c.customer_id = i.ENTITY_ID
JOIN ns.items it on it.item_id = tl.item_id
LEFT JOIN ns.ITEM_CLASSIFICATION it_class on it_class.list_id = it.ITEM_CLASSIFICATION_ID
LEFT JOIN TrueCosts tc ON tc.tranid = i.tranid AND tc.item_id = tl.item_id
WHERE list_item_name IS NOT NULL
AND i.tranid = '1262INV'

Answer 2

You have a couple of problems.
In your subquery you use the alias c for COSReport. You also use the alias c for customers in your outer query.
The bigger problem is that your subquery isn't correlated to your outer query at all. That's why it's summing up the entire table.
To correlate your subquery, you need to join (in the subquery) to one of the tables in the outer query. Not sure of your tables or data, but at a guess, I'd say you want to use ns.tinvoice i in a WHERE clause in your subquery.