C# 将带有联接的SQL查询转换为lambda表达式
不确定如何将以下sql转换为lambda表达式。我的数据库以1对多关系使用与表内容\u培训相关的引用完整性和表内容(1个内容可以有多个内容\u培训) 请尝试以下查询:C# 将带有联接的SQL查询转换为lambda表达式,c#,sql,entity-framework,linq-to-entities,sql-to-linq-conversion,C#,Sql,Entity Framework,Linq To Entities,Sql To Linq Conversion,不确定如何将以下sql转换为lambda表达式。我的数据库以1对多关系使用与表内容\u培训相关的引用完整性和表内容(1个内容可以有多个内容\u培训) 请尝试以下查询: var results = (from c in dbcontext.Contents join ct in dbcontext.Content_Trainings on c.ContentId equals ct.ContentId into t from rt in
var results = (from c in dbcontext.Contents
join ct in dbcontext.Content_Trainings on c.ContentId equals ct.ContentId into t
from rt in t.DefaultIfEmpty()
select new
{
c.ContentId,
c.Name,
TrainingTypeId = (int?)rt.TrainingTypeId
}).OrderBy(r => r.TrainingTypeId)
.ThenBy(r => r.Name);
我会经常使用查询语法,而不使用lambdas,即,
orderby x,y
。它会更可读。谢谢Abatishchev。在过去,我使用了“let”关键字,而不是您使用的“into t…t.DefaultIfEmpty()”。有什么区别?
var results = (from c in dbcontext.Contents
join ct in dbcontext.Content_Trainings on c.ContentId equals ct.ContentId into t
from rt in t.DefaultIfEmpty()
select new
{
c.ContentId,
c.Name,
TrainingTypeId = (int?)rt.TrainingTypeId
}).OrderBy(r => r.TrainingTypeId)
.ThenBy(r => r.Name);