Question

我有以下LINQ查询 -

var data = (from req in db.tblRequirements
       where req.guidRequirementId == guidRequirementId
             && (!db.ViewMIPRAlls.Any(x=>x.guidRequirementId == req.guidRequirementId))
       select new
       {
           guidRequirementId = req.guidRequirementId,
           strStatus = req.tblCodesRequirementStatus.strDescription,
           strNumber = req.ViewNumber.strAwardNumber,
           strOffice = req.tblOrganization.strAcronym,
           strCustomerOffice = req.tblOrganizationCustomer.strAcronym,
           strDescription = req.strDescription,
           strNotes = req.strNotes,
           strStatusId = req.strStatusId,
           strCompany = req.strCompany,
           strUpdatedBy = Person.GetPersonNameFromUserID(req.guidUserId),
           dtmUpdated = Requirement.UpdateTime(req.guidRequirementId),
           dtmEsitmatedEnd = (req.tblDates.Select(x=>x.dtmEnd) != null
              ? req.tblDates.Select(x=>x.dtmEnd.ToShortDateString()).ToString()
              : ""
           )
       }).OrderBy(x=>x.dtmEnd);

我无法按日期订购。此查询会导致以下错误：

无法将节点'ClientQuery'格式化为SQL执行。

Answer 1

在选择之前Orderby，或者在select

中创建的Orderby

Answer 2

如果您尝试按SQL中的字段排序，则OrderBy子句应位于select new之前。

您的LINQ语句可以转换为：

var data = 
    from req in db.tblRequirements
    from dates in req.tblDates
    where req.guidRequirementId == guidRequirementId
         && (!db.ViewMIPRAlls.Any(x=>x.guidRequirementId == req.guidRequirementId))
    order by dates.dtmEnd
    select new
    {
        guidRequirementId = req.guidRequirementId,
        strStatus = req.tblCodesRequirementStatus.strDescription,
        strNumber = req.ViewNumber.strAwardNumber,
        strOffice = req.tblOrganization.strAcronym,
        strCustomerOffice = req.tblOrganizationCustomer.strAcronym,
        strDescription = req.strDescription,
        strNotes = req.strNotes,
        strStatusId = req.strStatusId,
        strCompany = req.strCompany,
        strUpdatedBy = Person.GetPersonNameFromUserID(req.guidUserId),
        dtmUpdated = Requirement.UpdateTime(req.guidRequirementId),
        dtmEsitmatedEnd = (req.tblDates.Select(x=>x.dtmEnd) != null
            ? req.tblDates.Select(x=>x.dtmEnd.ToShortDateString()).ToString()
            : ""
        )
    }

请注意，根据tblRequirements和tblDates之间的关系类型，这可能会产生比初始选择更多的记录。为了解决这个问题，您需要考虑一种方法来汇总tblDates对应于tblRequirements记录的记录（也许只需要max(tblDates.dtmEnd)？）

Answer 3

尝试：

where req.guidRequirementId == guidRequirementId
        && (!db.ViewMIPRAlls.Any(x=>x.guidRequirementId == req.guidRequirementId))
order by req.dtmEnd     
select new

Linq查询不会让我按日期订购

3 个答案: