Linq查询使用Case语句 [英] Linq Query using Case statement

问题描述

我试图将下面的SQL查询转换为linq查询，但我无法做到。如果记录存在于另一个表中，我可以通过连接和连接如'*'这样的特殊字符来帮助如何使用这种类型的case语句。请帮我解决这个问题。

Hi,

I am trying to convert the below SQL query into linq query but am unable to do it. i can you please help how to usethis type of case statement by doing join and concatenation a special character like '*' if record exists in another table. Please help me how to do this.

Select Distinct A.MyID, Title + case when D.MyID is not null then ' *' else '' end  as Title , MagTitle FROM [MasterTitles] A left outer join TitleDetails D on A.[MyID] = D.[MyID] where [PropertyID] is not null ORDER BY [Title]

请帮助

Please help

推荐答案

它可能看起来像：

It might look like :

var qry = (from a in MasterTitles
          join d in TitleDetails on a.MyID equals d.MyID into grp
          from g in grp.DefaultIfEmpty()
          select new
          {
              MyID  = a.MyID,
              Title = grp != null ? string.Concat(a.Title, " *") : string.Empty
              //define next fields here
          }).Distinct();

如需了解更多信息，请参阅：如何：执行左外连接（C＃编程指南） [ ^ ]

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