SQL Group By issues with derived table - sql

Question

I'm attempting to create a table of all the latest payments made for an employee. The original table has all the payments made to an employee since they started. I created a derived table to give me only the records with the latest date in them.
I do still have some duplicates where the payment date is the same, in this case I want to add these payment together so they appear on one row instead.
Below is my working code;
SELECT T1.EmployeeCode
, T2.Staff_Number
, T2.Firstname + ' ' + T2.Surname AS Name
, T1.PaymentDate
, T1.p1
, T1.p2
, T1.p3
FROM DB1.dbo.PARTIFPSNI AS T1
--This section is supposed to return only the latest date
INNER JOIN (
SELECT EmployeeCode, MAX(PaymentDate) as MaxDate
FROM DB1.dbo.PARTIFPSNI
GROUP BY EmployeeCode
) T1A ON T1.EmployeeCode = T1A.EmployeeCode and T1.PaymentDate = T1A.MaxDate
LEFT JOIN DB2.dbo.Personnel_Records AS T2 ON (T1.EmployeeCode = T2.Staff_Number)
This returns the below;
I seem to have issues summing together p1, p2 & p3. I think this because I am trying to use the GROUP BY function twice.

Answer 1

SELECT T1.EmployeeCode ,
T2.Staff_Number ,
T2.Firstname + ' ' + T2.Surname AS Name ,
T1.PaymentDate ,
SUM(T1.p1) ,
SUM(T1.p2) ,
SUM(T1.p3)
FROM DB1.dbo.PARTIFPSNI AS T1
INNER JOIN ( SELECT EmployeeCode ,
MAX(PaymentDate) AS MaxDate
FROM DB1.dbo.PARTIFPSNI
GROUP BY EmployeeCode
) T1A ON T1.EmployeeCode = T1A.EmployeeCode
AND T1.PaymentDate = T1A.MaxDate
LEFT JOIN DB2.dbo.Personnel_Records AS T2 ON ( T1.EmployeeCode = T2.Staff_Number )
GROUP BY T1.EmployeeCode ,
T2.Staff_Number ,
T2.Firstname + ' ' + T2.Surname ,
T1.PaymentDate