SQL subquery with join to main query - sql

Question

I have this:
SELECT
SU.FullName as Salesperson,
COUNT(DS.new_dealsheetid) as Units,
SUM(SO.New_profits_sales_totaldealprofit) as TDP,
SUM(SO.New_profits_sales_totaldealprofit) / COUNT(DS.new_dealsheetid) as PPU,
-- opportunities subquery
(SELECT COUNT(*) FROM Opportunity O
LEFT JOIN Account A ON O.AccountId = A.AccountId
WHERE A.OwnerId = SU.SystemUserId AND
YEAR(O.CreatedOn) = 2022)
-- /opportunities subquery
FROM New_dealsheet DS
LEFT JOIN SalesOrder SO ON DS.New_DSheetId = SO.SalesOrderId
LEFT JOIN New_salespeople SP ON DS.New_SalespersonId = SP.New_salespeopleId
LEFT JOIN SystemUser SU ON SP.New_SystemUserId = SU.SystemUserId
WHERE
YEAR(SO.New_purchaseordersenddate) = 2022 AND
SP.New_SalesGroupIdName = 'LO'
GROUP BY SU.FullName
I'm getting an error from the subquery:
Column 'SystemUser.SystemUserId' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause.
Is it possible to use the SystemUser table join from the main query in this way?

Answer 1

As has been mentioned extensively in the comments, the error is actually telling you the problem; SU.SystemUserId isn't in the GROUP BY nor in an aggregate function, and it appears in the SELECT of the query (albeit in the WHERE of a correlated subquery). Any columns in the SELECT must be either aggregated or in the GROUP BY when using one of the other for a query scope. As the column in question isn't aggregated nor in the GROUP BY, the error occurs.
There are, however, other problems. Like mentioned ikn the comments too, your LEFT JOINs make little sense, as many of the tables you LEFT JOIN to require a column in that table to have a non-NULL value; it is impossible for a column to have a non-NULL value if a row was not found.
You also use syntax like YEAR(<Column Name>) = <int Value> in the WHERE; this is not SARGable, and thus should be avoided. Use explicit date boundaries instead.
I assume here that SU.SystemUserId is a primary key, and so should be in the GROUP BY. This is probably a good thing anyway, as a person's full name isn't something that can be used to determine who a person is on their own (take this from someone who shared their name, date of birth and post code with another person in their youth; it caused many problems on the rudimentary IT systems of the time). This results in a query like this:
SELECT SU.FullName AS Salesperson,
COUNT(DS.new_dealsheetid) AS Units,
SUM(SO.New_profits_sales_totaldealprofit) AS TDP,
SUM(SO.New_profits_sales_totaldealprofit) / COUNT(DS.new_dealsheetid) AS PPU,
(SELECT COUNT(*)
FROM dbo.Opportunity O
JOIN dbo.Account A ON O.AccountId = A.AccountId --A.OwnerID must have a non-NULL value, so why was this a LEFT JOIN?
WHERE A.OwnerId = SU.SystemUserId
AND O.CreatedOn >= '20220101' --Don't use YEAR(<Column Name>) = <int Value> syntax, it isn't SARGable
AND O.CreatedOn < '20230101') AS SomeColumnAlias
FROM dbo.New_dealsheet DS
JOIN dbo.SalesOrder SO ON DS.New_DSheetId = SO.SalesOrderId --SO.New_purchaseordersenddate must have a non-NULL value, so why was this a LEFT JOIN?
JOIN dbo.New_salespeople SP ON DS.New_SalespersonId = SP.New_salespeopleId --SP.New_SalesGroupIdName must have a non-NULL value, so why was this a LEFT JOIN?
LEFT JOIN dbo.SystemUser SU ON SP.New_SystemUserId = SU.SystemUserId --This actually looks like it can be a LEFT JOIN.
WHERE SO.New_purchaseordersenddate >= '20220101' --Don't use YEAR(<Column Name>) = <int Value> syntax, it isn't SARGable
AND SO.New_purchaseordersenddate < '20230101'
AND SP.New_SalesGroupIdName = 'LO'
GROUP BY SU.FullName,
SU.SystemUserId;

Answer 2

Doing such a sub-query is bad on a performance-wise point of view
better do it like this:
SELECT
SU.FullName as Salesperson,
COUNT(DS.new_dealsheetid) as Units,
SUM(SO.New_profits_sales_totaldealprofit) as TDP,
SUM(SO.New_profits_sales_totaldealprofit) / COUNT(DS.new_dealsheetid) as PPU,
SUM(csq.cnt) as Count
FROM New_dealsheet DS
LEFT JOIN SalesOrder SO ON DS.New_DSheetId = SO.SalesOrderId
LEFT JOIN New_salespeople SP ON DS.New_SalespersonId = SP.New_salespeopleId
LEFT JOIN SystemUser SU ON SP.New_SystemUserId = SU.SystemUserId
-- Moved subquery as sub-join
LEFT JOIN (SELECT a.OwnerId, YEAR(o.CreatedOn) as year, COUNT(*) cnt FROM Opportunity O
LEFT JOIN Account A ON O.AccountId = A.AccountId
GROUP BY a.OwnerId, YEAR(o.CreatedOn) as csq ON csq.OwnerId = su.SystemUserId and csqn.Year = 2022
WHERE
YEAR(SO.New_purchaseordersenddate) = 2022 AND
SP.New_SalesGroupIdName = 'LO'
GROUP BY SU.FullName
So you have a nice join and a clean result
The query above is untested