C# Lambda式LINQ对Entity进行分组求和与平均值
最编程
2024-08-10 15:57:19
...
1、单字段分组并求和：
var list = data.GroupBy(g => g.GoodsId).Select(e => new { GoodsId = e.Key, Qty = e.Sum(q => q.Qty) });
2、多字段分组求和：
var list = data.GroupBy(g => new { g.StorageId,g.GoodsId }).Select(e => new { GoodsId = e.Key, Qty = e.Sum(q => q.Qty) });
求平均值直接把Sum更换成：Average即可。
3、具有导航属性的类求和及分组：
var list = data.GroupBy(g => new { g.StorageId,g.GoodsId }).Select(e => new { StorageName = e.Select(i => i.Storage.Name).FirstOrDefault(), GoodsName = e.Select(i => i.Goods.Name).FirstOrDefault(), CategoryName = e.Select(i => i.Goods.CategoryName).FirstOrDefault(), Qty = e.Average(q => q.Qty) });