LINQ按表达式分组语法 [英] LINQ group by expression syntax
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问题描述
我有一个与此类似的T-SQL查询:
I've got a T-SQL query similar to this:
SELECT r_id, r_name, count(*)
FROM RoomBindings
GROUP BY r_id, r_name
我想使用LINQ来做同样的事情.到目前为止,我到了:
I would like to do the same using LINQ. So far I got here:
var rooms = from roomBinding in DALManager.Context.RoomBindings
group roomBinding by roomBinding.R_ID into g
select new { ID = g.Key };
如何提取count(*)和r_name部分?
How can I extract the count(*) and r_name part?
推荐答案
尝试一下:
var rooms = from roomBinding in DALManager.Context.RoomBindings
group roomBinding by new
{
Id = roomBinding.R_ID,
Name = roomBinding.r_name
}
into g
select new
{
Id = g.Key.Id,
Name = g.Key.Name,
Count = g.Count()
};
由Nick编辑-添加了方法链语法进行比较
var rooms = roomBinding.GroupBy(g => new { Id = g.R_ID, Name = g.r_name })
.Select(g => new
{
Id = g.Key.Id,
Name = g.Key.Name,
Count = g.Count()
});
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