如何将带有count的sql转换为linq

如何将其转换为linq

select i.CatName,COUNT(*) as n_items
from ixcxs i
group by i.CatName

或者lambda表达式会有帮助

试试看

ixcxs.GroupBy(g => g.CatName)
    .Select(s => new 
    {
        CatName = s.Key, 
        n_items = s.Count() 
    });

在查询语法中也是这样：

from i in ixcxs
group i by i.CatName into g
select new 
{
    CatName = g.Key,
    n_items = g.Count()
}

---

您无需从组中选择第一个项目即可获取CatName-请改用分组键：

var query = from i in ixcxs
            group i by i.CatName into g
            select new {
               CatName = g.Key,
               n_items = g.Count()
            };

与方法语法相同：

var query = ixcxs.GroupBy(i => i.CatName)
                 .Select(g => new { CatName = g.Key, n_items = g.Count() });

---

方法“Single”和“SingleOrDefault”只能用作最终查询操作。考虑在这个实例中使用方法“FrestRealDebug”。我在B.IXCXS组T中从T中通过< {T.CabNe}}将其编码为G。{g.Key.CatName，Total=g.Count（）}；但哪一个更为优化？好的，那是另一种方式