Sql 查询到在 Linq 中的左连接到实体答案

【问题标题】：Sql query to Left Join in Linq to entitySql 查询到在 Linq 中的左连接到实体
【发布时间】：2019-12-23 13:52:04
【问题描述】：

我下面有SQL查询

Select LC.*,LP.[LandingPageName] from [LandingPageCompanies] LC
 Left join [LandingPageContent] LP on LP.SubCategoryID=LC.SubCategoryID
 where  LC.[CategoryID]=17

我需要把它转换成LINQ to entity。

我尝试了以下查询，但它的工作方式为Inner join

 var data = (from t1 in dbSavingContainer.LandingPageCompanies
                        join t2 in dbSavingContainer.LandingPageContents on t1.SubCategoryID equals t2.SubCategoryID
                        where t1.CategoryID == CategoryID
                        select new
                        {
                            CategoryID = t1.CategoryID,
                            CompanyID = t1.CompanyID,
                            CompanyLink = t1.CompanyLink,
                            CompanyLogo = t1.CompanyLogo,
                            CompanyName = t1.CompanyName,
                            SubCategoryID = t1.SubCategoryID,
                            LandingPageName = t2.LandingPageName
                        }).ToList();

我缺乏的地方。 ?

【问题讨论】：

标签： sql-server c#-4.0 entity-framework-4 linq-to-entities

【解决方案1】：

谢谢..我刚刚使用下面的查询解决了它；）

 var data = (from t1 in dbSavingContainer.LandingPageCompanies
             join t2 in dbSavingContainer.LandingPageContents on t1.SubCategoryID equals t2.SubCategoryID
             into x from y in x.DefaultIfEmpty()
                   where t1.CategoryID == CategoryID
                     select new
                      {
                        CategoryID = t1.CategoryID,
                        CompanyID = t1.CompanyID,
                        CompanyLink = t1.CompanyLink,
                        CompanyLogo = t1.CompanyLogo,
                        CompanyName = t1.CompanyName,
                        SubCategoryID = t1.SubCategoryID,
                        LandingPageName = y.LandingPageName
                    }).ToList();

【讨论】：