hi,this query fails to these errorsThe multi-part identifier "arc87.balance" could not be bound.The multi-part identifier "arc87.balance" could not be bound.how can i fix it thanks for fast reply CREATE CLUSTERED INDEX IXC_Transaction_AccountID_Tarikh_TransactionID ON TransactionDetail (AccountID, tarikh, TransactionID)DECLARE @PrevAccountID bigINT = 0DECLARE @AccountRunningTotal decimal(38,0) = 0UPDATE TransactionDetail SET @AccountRunningTotal = t.balance = CASE WHEN t.AccountID = @PrevAccountID THEN @AccountRunningTotal + t.gardesh +arc87.balance ELSE t.gardesh+arc87.balance END, @PrevAccountID=t.AccountIDselect * from TransactionDetail tinner join arc87 onarc87.accountId=t.accountID