沒有加入Linq中

Question

我有我的查詢都加入這樣的

IQueryable<Auction> closed = 
       (from a in CurrentDataSource.Auctions 
       join p in CurrentDataSource.Payments 
        on a.Id equals p.AuctionId 
       where <some condition> 
       select a); 

我想真的是兩個表說給我哪裏有沒有加入與支付表或全部拍賣一些條件是成立的。我可以用T-SQL來做到這一點，但不知道如何用Linq做到這一點。你能幫我嗎？

Answer 1

您可以使用左外連接並檢查付款爲空，就像在T-SQL中一樣。

IQueryable<Auction> closed = 
       (from a in CurrentDataSource.Auctions 
       join p in CurrentDataSource.Payments 
        on a.Id equals p.AuctionId into temp 
       from t in temp.DefaultIfEmpty() 
       where t == null && <some condition> 
       select a);