Linq表达式相当于SQL查询

Question

Linq表达式与以下TSQL查询等效：

SELECT c.[CustomerId]
  ,c.[Name]
  , (SELECT COUNT(*) FROM Incidents WHERE CustomerId = c.CustomerId) AS IncidentsCount
  , (SELECT COUNT(*) FROM Opportunities WHERE CustomerId = c.CustomerId) AS OpportunitiesCount
  , (SELECT COUNT(*) FROM Visits WHERE CustomerId = c.CustomerId) AS VisitsCount
FROM [Customers] c

Answer 1

我没有在视觉工作室中对此进行双重检查，但这应该有效：

var x = (from c in Context.Customers
         select new {
             CustomerId = c.CustomerId,
             Name = c.Name,
             IncidentsCount = 
                 Context.Customers.Count(i => i.CustomerId == c.CustomerId),
             OpportunitiesCount = 
                 Context.Opportunities.Count(o => o.CustomerId == c.CustomerId),
             VisitsCount = 
                 Context.Visits.Count(v => v.CustomerId == c.CustomerId)
         });

更新：我将代码更改为更容易阅读。