Question

这是我第一次使用LINQ进行外连接。我认为我的查询很接近，但它返回的行数比应该多了很多。 LINQ查询创建的SQL返回2522条记录，而下面显示的sql等效项仅返回8，这是正确的数字。 linq查询中的iqid由常量设置，以便为我的测试用例隔离这一条记录。

我还想知道为什么在where语句中的两个bool评估不起作用。第一个是，但其他两个被注释掉，因为他们不会编译。我尝试使用＆＃34; ==＆＃34;像第一个语句和0而不是假，但都没有工作。

此查询有什么问题？

的LINQ：

public const string iqid = "9C01FFAE9B4E43D7853D811C8CF77B09";

var outerJoinQuery = from n in context.VCNOTE

                 // join the other table in and project into IEnumerable "noteGroup"
                 join l in context.VCNOTELINKS on n.IQID equals l.NOTE into noteGroup
                 from l in noteGroup.DefaultIfEmpty()

                 join c in context.SFACONTACT on l.CONTACT equals c.FIRSTNAME into contactGroup
                 from c in contactGroup.DefaultIfEmpty()

                 join f in context.VCFUND on l.FUND equals f.IQID into fundGroup
                 from f in fundGroup.DefaultIfEmpty()

                 join d in context.VCPROJECT on l.PROJECT equals d.LIBELLE into dealGroup
                 from d in dealGroup.DefaultIfEmpty()

                 join a in context.SFAACCOUNT on l.ACCOUNT equals a.NAME into companyGroup
                 from a in companyGroup.DefaultIfEmpty()

                 where n.IQID == iqid // && n.IQDELETED = false && l.IQDELETED = false

                 // project to an anonymous type and set properties to be displayed
                 select new
                 {
                     NoteID = l.NOTE,
                     FundID = l.FUND,
                     FundName = f.FUND,
                     ContactID = l.CONTACT,
                     ContactName = c.FIRSTNAME,
                     CompanyID = l.ACCOUNT,
                     CompanyName = a.NAME,
                     DealID = d.IQID,
                     DealName = d.LIBELLE
                 };

这就是我创建的sql（不是由linq查询生成的）看起来像返回8行并且是预期的结果。这也是linq创建的sql应该是这样的：

select  L.[IQID]
    ,L.[IQDELETED]
    ,L.[NOTE]           'Linked NoteID'
    ,L.[FUND]           'Linked FundID'
    ,F.Fund             'Linked Fund'
    ,L.[ACCOUNT]            'Linked CompanyID'
    ,A.NAME             'Linked Company'
    ,L.[PROJECT]            'Linked DealID'
    ,D.LIBELLE          'Linked Deal'
    ,L.[CONTACT]            'Linked ContactID'
    ,CONCAT(C.FIRSTNAME,' ',C.LASTNAME) 'Linked Contact' 

FROM VCNOTELINKS L

LEFT OUTER JOIN VCFUND F ON L.FUND = F.IQID
LEFT OUTER JOIN SFAACCOUNT A ON L.ACCOUNT = A.IQID
LEFT OUTER JOIN VCPROJECT D ON L.PROJECT = D.IQID
LEFT OUTER JOIN SFACONTACT C ON L.CONTACT = C.IQID

where L.note = '9C01FFAE9B4E43D7853D811C8CF77B09' AND L.IQDELETED = 0

连接多个表的linq外连接有什么问题？

0 个答案: