串联时性能低下

Question

I am using the following code to select my desired rows but the problem is it has low performance on select DocumentNumber column from other table that the problem is on this part ---> ('IN-'+@ItemStatus+'#'+chequeserial)

SELECT     
    Banking.ReceivedCheque.Date, Banking.ReceivedCheque.StatusDate,
    Banking.ReceivedCheque.DueDate, Banking.ReceivedCheque.ChequeSerial, 
    Banking.ReceivedCheque.BankName Banking.ReceivedCheque.CompanyInfoFK, 
    Banking.ReceivedCheque.FinancialPeriodFK, 
    Banking.ReceivedCheque.CreditGFK, Banking.ReceivedCheque.CreditID, 
    ReceivedFromAccount = dbo.getname(CreditID, CreditGFK, FinancialPeriodFK),
    DefBankAccount = dbo.getname(DefaultBankID, '4', FinancialPeriodFK), 
    Banking.ReceivedCheque.StatusFK,
    Banking.ChequeStatus.Title,
    (SELECT MAX(DocumentFK) 
     FROM Accounting.DocumentDetail 
     WHERE ItemFK = ('IN-' + @ItemStatus + '#' + chequeserial)  
       AND financialPeriodFK = @FinancialPeriodFK) AS DocumentNumber
FROM         
    Banking.ReceivedCheque 
INNER JOIN
    Banking.ChequeStatus ON Banking.ReceivedCheque.StatusFK = Banking.ChequeStatus.ChequeStatusID
WHERE
    ReceivedCheque.FinancialPeriodFK = @FinancialPeriodFK  
    AND Banking.ReceivedCheque.StatusFK = @StatusFK

Please let me know if there is any other solution to increase performance.

Answer 1

It looks like @ItemStatus is a scalar parameter. Can you do this portion of the operation once rather than for every row of the comparison? You'd eliminate many behind the scene concatenations.

set @InItemStatusPound = 'IN-'+@ItemStatus + '#'

ItemFK=(@InItemStatusPound+chequeserial)

This is typically one of the reason's lookup tables have foreign keys based on numeric values like int rather than string values. Is performing your join on an integer rather than a string that requires concatenation an option?

Note: If you could guarantee that the string would be less than 32 bits, using strings rather than int values is just fine. They're advantage is their compactness.

Sage Advice: Typically, if something hurts, figure out how not to do it.