Since your data is in two separate tables, I would first combine it into a single query using a Union Query (see this link for details on Union Queries:
https://support.office.com/en-sg/ar...on-query-3856f16c-0a22-43f2-8c23-29ec44acbc05).
So the SQL code for that would look something like this:
Code:
SELECT ClientID, [DepositDate] AS TransactionDate, [DepositValue] AS TransactionValue
FROM T_Deposits
UNION
SELECT ClientID, [WithdrawalDate] AS TransactionDate, 0-[WithdrawalValue] AS TransactionValue
FROM T_Withdrawals;
If you paste this code into the SQL View window of the Query Builder and view the results, you should see all your transactions combined together with a single TransactionDate field and single TransactionAmount field (where the Withdrawals show up as negatives).
Now, you can create a new query from this query, where you can add Criteria to limit it by ClientID and Transaction Dates, and use an Aggregate Query to get the SUM you want (GROUP BY ClientID, Sum the TransactionAmount field, and only use the TransactionDate field in your Criteria (do not Show, use "WHERE" in Totals Row for this field).
So if we called our Union Query "CombineTransactions", the SQL code of this Aggregate Query may look something like this:
Code:
SELECT ClientID, Sum(TransactionValue) AS TotalBalance
FROM CombineTransactions
WHERE TransactionDate Between #1/1/2014# And #1/31/2015#
GROUP BY ClientID
HAVING CombineTransactions.ClientID=1;