LINQ to SQL in和not in

Question

什么是in和not in中等於LINQ到SQL ？

例如

select * from table in ( ...)
and 
select * from table not in (..)

什么等於LINQ to SQL中的上述語句？

Answer 1

您使用， where <list>.Contains( <item> )

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

或者您可以預定義列表：

int[] ids = {1, 2, 3};

var query = from item in context.items
            where ids.Contains( item.id )
            select item;

對於'NOT'的情況，只需添加'！' 'Contains'語句之前的運算符。

Answer 2

我對你的問題感到困惑。 in並not in在查詢中的字段進行操作，但你不能在你的例子查詢中指定的字段。 所以它應該是這樣的：

select * from table where fieldname in ('val1', 'val2')

要么

select * from table where fieldname not in (1, 2)

在LINQ to SQL中等效的那些查詢將是這樣的：

List<string> validValues = new List<string>() { "val1", "val2"};
var qry = from item in dataContext.TableName
          where validValues.Contains(item.FieldName)
          select item;

還有這個：

List<int> validValues = new List<int>() { 1, 2};
var qry = from item in dataContext.TableName
          where !validValues.Contains(item.FieldName)
          select item;

Answer 3

請嘗試使用SQL而不是IN

var v = from cs in context.Sal_Customer
         join sag in context.Sal_SalesAgreement
         on cs.CustomerCode equals sag.CustomerCode
         where
          !(
               from cus in context.Sal_Customer
               join
               cfc in context.Sal_CollectionFromCustomers
               on cus.CustomerCode equals cfc.CustomerCode
               where cus.UnitCode == locationCode &&
                     cus.Status == Helper.Active &&
                     cfc.CollectionType == Helper.CollectionTypeDRF
               select cus.CustomerCode
           ).Contains(cs.CustomerCode) &&
           cs.UnitCode == locationCode &&
           cs.Status == customerStatus &&
           SqlFunctions.DateDiff("Month", sag.AgreementDate, drfaDate) < 36
           select new CustomerDisasterRecoveryDetails
           {
             CustomerCode = cs.CustomerCode,
             CustomerName = cs.CustomerName,
             AgreementDate = sag.AgreementDate,
             AgreementDuration = SqlFunctions.DateDiff("Month", sag.AgreementDate, drfaDate)
   };

請嘗試使用SQL IN

context.Sal_PackageOrItemCapacity.Where(c => c.ProjectCode == projectCode && c.Status == Helper.Active && c.CapacityFor.Contains(isForItemOrPackage)).ToList();