// Existing SQL statement ****************************
//****************************************************
UPDATE tServiceID
SET tServiceID.CurrentRent = TT.RentAmt,
 tServiceID.CurrentCalls = TT.CallAmt
FROM (

SELECT tTransaction.ServiceID, tTransaction.ServiceTypeID,
 Sum(CASE tTransactionGroup.Description WHEN 'RENT' THEN tTransaction.AmountExGST ELSE 0 END) AS RentAmt,
 Sum(CASE tTransactionGroup.Description WHEN 'CALL' THEN tTransaction.AmountExGST ELSE 0 END) AS CallAmt
FROM ((tTransaction
LEFT JOIN tServiceID ON tTransaction.ServiceID = tServiceID.ID)
LEFT JOIN tTransactionType ON tTransaction.TransactionTypeID = tTransactionType.ID)
LEFT JOIN tTransactionGroup ON tTransactionType.TransactionGroupID = tTransactionGroup.ID
WHERE tTransaction.BatchID = 11111
AND tTransaction.RevenueFlag <> 1
AND tServiceID.ServiceTypeID = tTransaction.ServiceTypeID
GROUP BY tTransaction.ServiceID, tTransaction.ServiceTypeID

) AS TT
WHERE tServiceID.ID = TT.ServiceID
AND tServiceID.ServiceTypeID = TT.ServiceTypeID
*******************************************************
// Is this better/same for rent only? *****************

UPDATE tServiceID
SET tServiceID.CurrentRent = TT.RentAmt
FROM (

SELECT tTransaction.ServiceID, tTransaction.ServiceTypeID,
 Sum(tTransaction.AmountExGST) AS RentAmt
FROM ((tTransaction
LEFT JOIN tServiceID ON tTransaction.ServiceID = tServiceID.ID)
LEFT JOIN tTransactionType ON tTransaction.TransactionTypeID = tTransactionType.ID)
LEFT JOIN tTransactionGroup ON tTransactionType.TransactionGroupID = tTransactionGroup.ID
WHERE tTransaction.BatchID = 11111
AND tTransaction.RevenueFlag <> 1
AND tTransactionGroup.Description LIKE 'RENT'
AND tServiceID.ServiceTypeID = tTransaction.ServiceTypeID
GROUP BY tTransaction.ServiceID, tTransaction.ServiceTypeID

) AS TT
WHERE tServiceID.ID = TT.ServiceID
AND tServiceID.ServiceTypeID = TT.ServiceTypeID

*******************************************************
// Is this better for call only? ********************

UPDATE tServiceID
SET tServiceID.CurrentCalls = TT.CallAmt
FROM (

SELECT tTransaction.ServiceID, tTransaction.ServiceTypeID,
 Sum(tTransaction.AmountExGST) AS CallAmt
FROM ((tTransaction
LEFT JOIN tServiceID ON tTransaction.ServiceID = tServiceID.ID)
LEFT JOIN tTransactionType ON tTransaction.TransactionTypeID = tTransactionType.ID)
LEFT JOIN tTransactionGroup ON tTransactionType.TransactionGroupID = tTransactionGroup.ID
WHERE tTransaction.BatchID = 11111
AND tTransaction.RevenueFlag <> 1
AND tTransactionGroup.Description LIKE 'CALL'
AND tServiceID.ServiceTypeID = tTransaction.ServiceTypeID
GROUP BY tTransaction.ServiceID, tTransaction.ServiceTypeID

) AS TT
WHERE tServiceID.ID = TT.ServiceID
AND tServiceID.ServiceTypeID = TT.ServiceTypeID