c# - 使用实体框架组合两个表

Question

我有以下查询：

{
 SELECT A.Id, C1.FullName AS APerson, C2.FullName As BPerson
 FROM TableA AS A
   LEFT JOIN TableC AS C1 ON A.FK_PersonA = C1.Id
   LEFT JOIN TableC AS C2 ON A.FK_PersonB = C2.Id
 UNION
 SELECT B.Id, B.FullName1 AS APerson, B.FullName2 AS BPerson
 FROM TableB AS B
}

我想将其转换为实体框架 lambda 查询，这可能吗？

数据模型

Answer 1

首先，您应该为您的模型创建存储库。在此处阅读有关此内容。所以，你可以使用这个：

var ret = 
    (from taRec in TableA.GetAll()
    join tc1 in TableC.GetAll on taRec.FK_PersonA equals tc1.Id
      into tcRecs1
    from tcRec1 in tcRecs1.DefaultIfEmpty()
    join tc2 in TableC.GetAll on taRec.FK_PersonB equals tc2.Id
      into tcRecs2
    from tcRec2 in tcRecs2.DefaultIfEmpty()
    select new {
        taRec.Id, APerson = tcRec1.FullName, BPerson = tcRec2.FullName
    }).Union(
        from tbRec in TableB.GetAll()
        select new {
            tbRec.Id, APerson = tbRec.FullName, BPerson = tbRec.FullName
    });