SQL进入涉及SUM（）的LinQ语句[重复]

Question

我无法将下面的 SQL 代码转换为 LinQ 方法语法

select top(5) MerchantUserId,sum(TotalAmount) as TotalAmount from OrderTransaction 
group by MerchantUserId 
order by TotalAmount desc

我已经尝试过，但我无法让 LinQ 适应函数 SUM

var list = _ApplicationDbContext.OrderTransaction
          .Where(x => x.Status != 0)
          .GroupBy(x => x.MerchantUserId)
          .Select(x => new DashboardMerchantStoreRankingByOrderAmount { MerchantUserId = x.Key })
          .OrderByDescending(x => x.TotalAmount)
          .Take(5)
          .ToList();

以下是用于存储单个记录的类

public class DashboardMerchantStoreRankingByOrderAmount
{
    public Guid MerchantUserId { get; set; }
    public double TotalAmount { get; set; }
    
}

基本上，我想根据订单金额检索前 5 名表现最佳的商家。

Answer 1

以下查询完全实现了 sql 查询。

var query = _ApplicationDbContext.OrderTransaction.Where(x => x.Status != 0)
  .GroupBy(a => a.MerchantUserId)
  .Select(group =>
     new DashboardMerchantStoreRankingByOrderAmount
     {
         MerchantUserId = group.Key,
         TotalAmount = group.OrderByDescending(a => a.TotalAmount).Select(a => a.TotalAmount).Take(5).Sum()
     }).ToList();