Left加入实体框架

Question

我想将此SQL转换为实体框架LINQ，但不工作。

我的SQL代码：

SELECT 
    s.Id, 
    s.OriginalPhotoBlobId, 
    s.PhotoBlobExtension, 
    ISNULL(s.ProductSkuKey, p.[Key]) as [Key], 
    p.Name, 
    ISNULL(sp.Price, 0) as [Price], 
    sp.PriceList_Id 
FROM SKUs s 
INNER JOIN Products p on p.Id = s.Product_Id 
LEFT JOIN SKUPrices sp on sp.SKU_Id = s.Id 

我的实体框架代码：

var db = this.Context; 
var prices = from s in db.SKUs 
       join p in db.Products on s.Product equals p 
       join sp in db.SKUPrices on s equals sp.SKU into gj 
       from spss in gj.DefaultIfEmpty() 
       select new PriceListItem 
       { 
       Id = s.Id, 
       BlobId = s.OriginalPhotoBlobId, 
       BlobExtension = s.PhotoBlobExtension, 
       Key = ((s.ProductSkuKey == null || s.ProductSkuKey.Trim() == string.Empty) ? p.Key : s.ProductSkuKey), 
       Name = p.Name, 
       Price = (spss == null ? default(double) : spss.Price), 
       }; 

Answer 1

我认为你应该使用navigation性能。导航属性用于导航数据中的关系。

Answer 2

试着加入的属性而不是类

var prices = from s in db.SKUs 
       join p in db.Products on s.Product_Id equals p.Id 
       join sp in db.SKUPrices on sp.SKU_Id = s.Id into gj 
       from sp in gj.DefaultIfEmpty() 
       select new PriceListItem 
       { 
       Id = s.Id, 
       BlobId = s.OriginalPhotoBlobId, 
       BlobExtension = s.PhotoBlobExtension, 
       Key = ((s.ProductSkuKey == null || s.ProductSkuKey.Trim() == string.Empty) ? p.Key : s.ProductSkuKey), 
       Name = p.Name, 
       Price = (sp == null ? default(double) : sp .Price), 
       };