C# LINQ group by 表达式语法
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时间：2020-08-06 20:54:42 来源:igfitidea点击:
LINQ group by expression syntax
提问by agnieszka
I've got a T-SQL query similar to this:
我有一个与此类似的 T-SQL 查询：
SELECT r_id, r_name, count(*)
FROM RoomBindings
GROUP BY r_id, r_name
I would like to do the same using LINQ. So far I got here:
我想使用 LINQ 做同样的事情。到目前为止，我到了这里：
var rooms = from roomBinding in DALManager.Context.RoomBindings
group roomBinding by roomBinding.R_ID into g
select new { ID = g.Key };
How can I extract the count(*) and r_name part?
如何提取 count(*) 和 r_name 部分？
采纳答案by bruno conde
Try this:
尝试这个：
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()
};
Edit by Nick - Added method chain syntax for comparison
由 Nick 编辑 - 添加了用于比较的方法链语法
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()
});
