我有一个现有的 LINQ to Entities 查询，我需要添加一个 case 语句。在伪中，如果列 CertType = 0，则从 db.LWCertCols 中提取评论，否则从 db.LWCertLoans 中提取评论（评论列在两个表中都存在）。我知道以下不起作用，但请注意 if 语句。我怎么能写它来工作？
aryData =
(From lwl In db.LWCertLoans _
Join c In db.Loans _
On c.LoanNum Equals lwl.LoanNum _
Join p In db.LWCertColls _
On lwl.CertID Equals p.CertID _
Join r In db.RespCntrs _
On r.BranchNum Equals c.BranchNum _
Join cert In db.LWCerts
On cert.LWCertID Equals lwl.CertID _
Where p.LoanNum = lwl.LoanNum _
Select New With { _
.ToBeProcessedDate = cert.ToBeProcessedDate, _
.CertType = cert.CertType, _
.CertCollID = p.CertCollID, _
.CertificateID = p.CertID, _
.LoanNumberTypeAndCurrencyCombined = c.LoanNum, _
.LoanType = c.LoanType, _
.CurrType = r.CurrType, _
.CollanteralBalance = c.ColCurBal, _
.SalesAdditions = p.Sales, _
.CreditMemos = p.Credits, _
.CashRemovals = p.NetCollect, _
.NonDilutiveAdjustment = p.PlusAdj, _
.Discounts = p.Discounts, _
.NonARCash = p.NonARCash, _
.DilutiveAdjustment = p.NegAdj, _
.LWCertCollsComments = p.Comments, _
.StatusCode = p.StatusCode, _
.CertLoanID = lwl.CertLoanID, _
.Modified = lwl.Modified, _
.LoanNum = lwl.LoanNum, _
.EffectiveDate = lwl.EffectiveDate, _
.RepWireNumber = lwl.RepWireNumber, _
.Advance = lwl.Advance, _
.ModifiedDate = lwl.ModifiedDate, _
.DDAAccountName = lwl.DDAAccountName, _
.LWCertLoansComments = lwl.Comments, _
if cert.CertType = 0 then
.Comment = p.Comments
else
.Comment = lwl.Comments
end if
}).ToArray()