LINQ查询忽略所有重复的ID [英] LINQ Query that omits any duplicate IDs

问题描述

我有两个桌子.为了简单起见，将它们称为表A和表B，

I have two tables. For simplistic reasons will call them Table A and Table B,

表A:

ID int(PK)

客户名称 varchar

customeraddy varchar

服务中 布尔值

等 varchar

等 varchar

表B:

PKID int(PK)

ID int()

线路名称​​ varchar

linename varchar

只需寻找一个LINQ查询，即可从ID列(其中inservice =="true")的表A 和表B 的联接表中选择所有值忽略基于ID的任何重复项(因为表B具有ID的多个重复项).

Just looking for a LINQ query that can select all values from a joined table of Table A and Table B on the ID column where inservice == "true" that omits any duplicates based on ID (because Table B has multiple duplicates of ID).

到目前为止，这就是我所拥有的:

So far this is what i have:

from x in db.tableA
join y in db.tableB on x.id equals y.id
where x.inservice == "true"
select y);

推荐答案

假定表中的inservice是bool而不是string，并假设您同时希望tableA和tableB行，其中tableB只有一个匹配行，

Assuming inservice is bool as in your table description and not string, and assuming you want both tableA and tableB rows where tableB has only one matching row,

var AjoinB = from x in db.tableA
             where x.inservice
             join y in db.tableB on x.id equals y.id
             group new { x, y } by x.id into xyg
             where xyg.Count() == 1
             select xyg;

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