在linq中使用左联接查询

本文介绍了在linq中使用左联接查询的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

你好，我想在linq中进行查询，但我想我需要一些帮助...

Hello I 'm trying to do a query in linq but I think I need some help...

我有两个表:langAvailable和Translations 即使没有翻译，我也要一个线"

I have two table: langAvailable and Translations I want a 'line' even if theres no translation recorded

例如:

LangId: 1 TranslationID:10 Translation: Hello LangId: 2 TranslationID:10 Translation: Bonjour LangId: 1 TranslationID:11 Translation: Thanks LangId: 2 TranslationID:11 Translation:

这就是我要做的:

Dim query = From c In db.LangAvailable _ Join o In db.Translate On c.ID_Lang Equals o.Lang_ID _ Where o.TranslationID = 243 _ Select New With {c.LangId, o.Translation}

如果翻译表中没有翻译，这只会给我一条记录... 知道我怎么能得到吗?

This only give me one record if there s no translation in the translate table... Any idea how I can get that?

感谢

推荐答案

您可以使用组联接"来执行您要尝试执行的操作.试试这个:

You can use Group Join to do what you're trying to do. Try this:

Dim query = From c In db.LangAvailable _ Group Join o In db.Translate On c.ID_Lang Equals o.Lang_ID Into Group _ From o In Group.DefaultIfEmpty() _ Where o.TranslationId = 243 _ Select LangId = c.ID_Lang, Translation = If(o.Translation Is Nothing, Nothing, o.Translation)