Question

我如何在林克的 s下书写字

select * from Product where ProductTypePartyID IN
(
    select Id from ProductTypeParty where PartyId = 34
)

Answer 1

除语气差异外,你实际上可以这样写。

from p in ctx.Product
where (from ptp in ctx.ProductTypeParty
       where ptp.PartyId == 34
       select ptp.Id).Contains(p.ProductTypePartyID)
select p

我更喜欢使用现有标准,但:

from p in ctx.Product
where (from ptp in ctx.ProductTypeParty
       where ptp.PartyId == 34
       && ptp.Id == p.ProductTypePartyID).Any()
select p

我预计,这一表格将决心在制作的SQ中采用EXISTS(SlectT * >。

如果业绩有巨大差异,你就希望说明两者。

Answer 2

There is no direct equivalent in LINQ. Instead you can use contains () or any other trick to implement them. Here s an example that uses Contains:

String [] s = new String [5];
s [0] = "34";
s [1] = "12";
s [2] = "55";
s [3] = "4";
s [4] = "61";

var  result = from d in  context.TableName
              where s.Contains (d.fieldname)
              select d;

详细检查这一联系:in article Linq

int[] productList = new int[] { 1, 2, 3, 4 };


var myProducts = from p in db.Products
                 where productList.Contains(p.ProductID)
                select p;

Answer 3

与此类似

var partyProducts = from p in dbo.Product 
                    join pt in dbo.ProductTypeParty on p.ProductTypePartyID equal pt.PartyId 
                    where pt.PartyId = 34 
                    select p

Answer 4

您在条款中使用该术语。

根据这些路线(未测试):

var results = Product.Where(product => ProductTypeParty
                                            .Where(ptp => ptp.PartyId == 34)
                                            .Select(ptp => ptp.Id)
                                            .Contains(product.Id)
                           );

友情链接