Where statement in ssrs expression

=Sum(IIF(Fields!DiscountAmount.Value <> 0, Fields!Qty.Value, 0))* Sum(Fields!DiscountAmount.Value)

Selected design name in print mgmt : Sales Invoice

static void reportName(Args _args)
{
   
    PrintMgmtDocInstance    printMgmtDocInstance;
    printMgmtReportFormat   printMgmtReportFormat;
    PrintMgmtSettings        printMgmtSettings;
    PrintMgmtReportFormatName  reportFormatName;
   
    select documentType, RecId from printMgmtDocInstance
        where printMgmtDocInstance.DocumentType ==PrintMgmtDocumentType::SalesOrderInvoice
        join parentId, ReportFormat from printMgmtSettings
        where printMgmtSettings.ParentId == printMgmtDocInstance.RecId
        join RecId, documentType, Name from printMgmtReportFormat
        where printMgmtReportFormat.RecId   ==  printMgmtSettings.ReportFormat
        && printMgmtReportFormat.DocumentType   ==  PrintMgmtDocumentType::SalesOrderInvoice;
   
    info(printMgmtReportFormat.Name);
}