Question

我正在尝试查询3级表ef_staff表3次，以获得每行3个diff人员对象。如何在LINQ中翻译？

SELECT a.a_appraisalid, a.a_year, c.s_staffName, c2.s_staffName, c3.s_staffName
FROM   ef_appraisal a, idp_application b, ef_staff c, ef_staff c2, ef_staff c3
WHERE  a.a_appraisalid = b.a_appraisalid AND
       a.a_staffid = c.s_staffid AND
       a.a_appraisedby = c2.s_staffid AND
       a.a_reviewedby = c3.s_staffid

我一直在尝试很多方法但是在第二个和第二个方面仍然存在“类型推断失败”的错误。第3次参加工作人员。我在这里缺少什么？

from application in applications

join appraisal in pmsEntities.ef_appraisal on application.a_appraisalid equals appraisal.a_appraisalid

join staff in pmsEntities.ef_staff on appraisal.a_staffid equals staff.s_staffid

join appraiser in pmsEntities.ef_staff on staff.s_appraisedby equals appraiser.s_staffid into ap

from appraiser in ap.DefaultIfEmpty() 

join reviewer in pmsEntities.ef_staff on staff.s_reviewedby equals reviewer.s_staffid into rv

from reviewer in rv.DefaultIfEmpty() 

join company in pmsEntities.ef_company on appraisal.a_companyid equals company.c_companyid into jc

from company in jc.DefaultIfEmpty()

select appraisal, staff.staffName, appraiser.staffName, reviewer.staffName, company.compName

Answer 1

我修正了错误。员工对象的第一级连接应该链接到第二级员工对象，如下所示：

join staff in pmsEntities.ef_staff on appraisal.a_staffid equals staff.s_staffid into staffj

                    from staff1 in staffj

                    join appraiser in pmsEntities.ef_staff on staff1.s_appraisedby equals appraiser.s_icno into staff2

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希望有所帮助

C＃Linq连接多层表

1 个答案: