Group by in subquery and base query sql server
No, you will not be able to do that as the SUB QUERY in the SELECT list will then return more that 1 Value.
You need to do it in a SUB Query in the FROM clause
Something like
SELECT Day,
SUM(Regular + Extra + Overtime) AS [Potential Hours],
SubSum AS [Billed Hours]
FROM Billable AS Billable1 LEFT JOIN
(
SELECT Day,
SUM(Extra + Regular + Overtime) AS SubSum
FROM dbo.TICPlus_Effort_Billable_Only
WHERE (Manager NOT LIKE '%manager1%')
GROUP BY Day
) s ON Billable1.Day = s.Day
GROUP BY Day