c# - 在 EF 中使用 sql 查询

Question

我通过以下方式从数据库中获取数据:

 result = (from d in context.FTDocuments
                          join f in context.FTDocFlags on d.ID equals f.DocID into fgrp
                          from x in fgrp.DefaultIfEmpty()
                          where d.LevelID == levelID && x.UserID == userID && d.Status.Equals(DocumentStatus.NEW)
                          select new Entities.Document
                          {
                              ArrivalDate = d.ArrivalDate.Value,
                              BundleReference = d.BundleRef,
                              CreatedDate = d.CreatedDate,
                              CustomerID = d.CustomerID,
                              DocType = d.DocType.Value,
                              GuidID = d.DocGuid,
                              ID = d.ID,
                              LastExportID = d.LastExpID,
                              LevelID = d.LevelID,
                              ProfileID = d.ProfileID,
                              ScanDate = d.ScanDate.Value,
                              ScanOperator = d.ScanOperator,
                              SenderEmail = d.SenderEmail,
                              Status = d.Status,
                              VerifyOperator = d.VerOperator,
                              FlagNo = x == null ? 0 : x.FlagNo,
                              FlagUserID = x == null ? 0 : x.UserID
                          }).ToList();

现在，我尝试通过使用 sql 查询来实现这一点:

var test = context.Database.SqlQuery<string>("select *from FTDocument d left outer join FTDocFlag f on d.ID=f.DocID").ToList();

但是得到如下错误:

The data reader has more than one field. Multiple fields are not valid for EDM primitive or enumeration types

是否可以像上面那样使用复杂的查询？

我使用 EF 6.0。

Answer 1

您的查询没有返回单个字符串。像这样使用:

var test = context.Database.SqlQuery<Entities.Document>("...");