пытаясь присоединить предложение where к выражению sql

Question

Привет, я пытаюсь присоединить предложение where к SQL-выражению, как это

    public static DataTable paymentType(string paymenttype, string ddproviders, string overdue)
    { 

                string paymenttypestr = "";
    string ddproviderstr = "";


    if (paymenttype != "")
    {
        paymenttypestr = string.Format("AND membertomships.memberToMship_PayMethod = '{0}'", paymenttype);        

    }
    if (ddproviders != "")
    {
        ddproviderstr = string.Format("AND ddproviders.ddProvider_Name = '{0}'", ddproviders);

    }
    if (overdue == "OverDue-Now")
    { 
       string sql += @"WHERE memberpaysched.memberPaySched_dateDue < NOW() AND memberpaysched.memberPaySched_amountDue > memberpaysched.memberPaySched_amountPaid ";

    }

    string  sql = string.Format(
                @"SELECT    members.member_Id,
                   members.member_Lastname As Last_name,
                   members.member_Firstname AS First_name,
                   members.member_PostCode  As Post_Code, 
                   ddaccounts.ddAccount_DdReference As dd_reference,
                   ddproviders.ddProvider_Name As dd_providername,
                   memberToMship_ChargePerPeriod As monthly_amount,
                   mshiptypes.mshipType_Name As Membership_type,
                   mshipstatustypes.mshipStatusType_Name As Status,
                   membertomships.memberToMship_EndDate As Expiry_Date,
                   membertomships.memberToMship_PayMethod As payment_method
                   FROM members 
                   LEFT JOIN membertomships ON membertomships.member_Id = members.member_Id
                   LEFT JOIN memberpaysched ON memberpaysched.memberPaySched_memberId = members.member_Id
                   LEFT OUTER JOIN ddaccounts ON ddaccounts.member_Id = members.member_Id
                   LEFT OUTER JOIN  ddproviders ON  ddaccounts.ddProvider_Id=ddproviders.ddProvider_Id 
                   LEFT JOIN   mshipstatustypes ON mshipstatustypes.mshipStatusType_Id = membertomships.mshipStatusType_Id
                   LEFT JOIN   mshipoptions ON mshipoptions.mshipOption_Id = membertomships.mshipOption_Id
                   LEFT JOIN   mshiptypes ON mshiptypes.mshipType_Id = mshipoptions.mshipType_Id
                   WHERE       members.member_Active LIKE 'y%'
                   AND               mshipoptions.mshipOption_Period = 'month' 
                   AND               (mshipstatustypes.mshipStatusType_Id <> 5)
                   {0}
                   {1}     
                   ORDER BY members.member_Lastname",
                   paymenttypestr, ddproviderstr);
      return getdata(sql,mf);
    }

но выдает ошибку в этой строке, как ";" этот символ необходим;

    string sql += @"WHERE memberpaysched.memberPaySched_dateDue < NOW() AND memberpaysched.memberPaySched_amountDue > memberpaysched.memberPaySched_amountPaid "; 

Я хочу добавить предложение where, если просрочено == "overdue-now"

как я могу добавить это предложение в соответствии с условием

поможет ли кто-нибудь в этом ....

Modified Query :   string sql += @"memberpaysched.memberPaySched_dateDue < NOW() AND memberpaysched.memberPaySched_amountDue > memberpaysched.memberPaySched_amountPaid";

все еще показывал эту ошибку "Неверный срок действия выражения + ="

Answer 1

Итак, если просрочено == "OverDue-Now", вы объявляете строку sql и + = ее? Но затем вы перезаписываете строку, которую, как вы думали, только что создали.

Я думаю, это то, чего вы пытаетесь достичь:

if (overdue == "OverDue-Now")     
{
   string isoverduestr = @"AND memberpaysched.memberPaySched_dateDue < NOW() AND memberpaysched.memberPaySched_amountDue > memberpaysched.memberPaySched_amountPaid ";      
}
else
{
   string isoverduestr = @"";
}

string  sql = string.Format(
            @"SELECT    members.member_Id,
               members.member_Lastname As Last_name,
               members.member_Firstname AS First_name,
               members.member_PostCode  As Post_Code, 
               ddaccounts.ddAccount_DdReference As dd_reference,
               ddproviders.ddProvider_Name As dd_providername,
               memberToMship_ChargePerPeriod As monthly_amount,
               mshiptypes.mshipType_Name As Membership_type,
               mshipstatustypes.mshipStatusType_Name As Status,
               membertomships.memberToMship_EndDate As Expiry_Date,
               membertomships.memberToMship_PayMethod As payment_method
               FROM members 
               LEFT JOIN membertomships ON membertomships.member_Id = members.member_Id
               LEFT JOIN memberpaysched ON memberpaysched.memberPaySched_memberId = members.member_Id
               LEFT OUTER JOIN ddaccounts ON ddaccounts.member_Id = members.member_Id
               LEFT OUTER JOIN  ddproviders ON  ddaccounts.ddProvider_Id=ddproviders.ddProvider_Id 
               LEFT JOIN   mshipstatustypes ON mshipstatustypes.mshipStatusType_Id = membertomships.mshipStatusType_Id
               LEFT JOIN   mshipoptions ON mshipoptions.mshipOption_Id = membertomships.mshipOption_Id
               LEFT JOIN   mshiptypes ON mshiptypes.mshipType_Id = mshipoptions.mshipType_Id
               WHERE       members.member_Active LIKE 'y%'
               AND               mshipoptions.mshipOption_Period = 'month' 
               AND               (mshipstatustypes.mshipStatusType_Id <> 5)
               {0}
               {1}
               {2}     
               ORDER BY members.member_Lastname",
               paymenttypestr, ddproviderstr, isoverduestr);

Answer 2

На первый взгляд у вас есть 2 предложения. Измените тот, который вы добавляете в AND, и посмотрите, что произойдет.

Answer 3

Я не эксперт по .NET, но я, вероятно, изменил бы:

if (overdue == "OverDue-Now")     
{
     string sql += @"WHERE memberpaysched.memberPaySched_dateDue < NOW() AND memberpaysched.memberPaySched_amountDue > memberpaysched.memberPaySched_amountPaid ";      
} 

на:

if (overdue == "OverDue-Now")     
{
     sql += @"AND memberpaysched.memberPaySched_dateDue < NOW() AND   memberpaysched.memberPaySched_amountDue > memberpaysched.memberPaySched_amountPaid ";      
} 

(т.е. удалите ключевое слово string и замените AND на WHERE)

и поместите его ПОСЛЕ основного блока SQL (т. Е. Там, где вы объявляете строковую переменную sql) ..