问题描述
我有员工和团队之间的多对多关系.以下 linq 语句
i have many to many relationship between employee and group. following linq statement
int[] GroupIDs = {6,7}; var result = from g in umGroups join empGroup in umEmployeeGroups on g.GroupID equals empGroup.GroupID where GroupIDs.Contains(g.GroupID) select new { GrpId = g.GroupID,EmployeeID = empGroup.EmployeeID };
返回 groupid 和雇员 ID.结果是
returns groupid and the employeeid. and result is
GrpId | EmployeeID 6 | 18 6 | 20 7 | 19 7 | 20
我需要删除员工 ID 重复的行,例如雇员id = 20的行中的任何一项
谢谢
I need to remove the rows for which the employeeid is repeating e.g. any one of the row with employeeid= 20
Thanks
推荐答案
好吧,如果你不在乎解雇了哪位员工,你可以试试这样的:
Okay, if you don't care which employee is removed, you could try something like:
var result = query.GroupBy(x => x.EmployeeId) .Select(group => group.First());
您还没有指定这是在 LINQ to SQL、LINQ to Objects 还是其他东西中...我不知道这将是什么 SQL 翻译.如果您处理的数据量相对较少,您总是可以强制执行最后一点:
You haven't specified whether this is in LINQ to SQL, LINQ to Objects or something else... I don't know what the SQL translation of this would be. If you're dealing with a relatively small amount of data you could always force this last bit to be in-process:
var result = query.AsEnumerable() .GroupBy(x => x.EmployeeId) .Select(group => group.First());
那时你实际上可以使用 MoreLINQ ,它有一个方便的 DistinctBy 方法:
At that point you could actually use MoreLINQ which has a handy DistinctBy method:
var result = query.AsEnumerable() .DistinctBy(x => x.EmployeeId);