linq not in 查询

时间：2015-11-4类别：编程学习

linq not in 查询

下面以linq to sql的实例介绍 not in 查询和 in查询，linq的用法类似

一、T-SQL的IN


Select ProductID, ProductName, CategoryID
From dbo.Products
Where CategoryID in (1, 2)

二、LINQ to SQL 实现IN


var queryResult = from p in db.Products
where (new int[] ...{1,2}).Contains(p.CategoryID)
select p;

三、T-SQL的NOT IN


Select ProductID, ProductName, CategoryID
From dbo.Products
Where CategoryID not in (1, 2)

四、LINQ to SQL 实现 NOT IN


var queryResult = from p in db.Products
where !(new int[] ...{1,2}).Contains(p.CategoryID)
select p;

五、LINQ to SQL 实现 NOT IN子查询


from a in TableA where !(from b in TableB Where ... select b.Id).Contains(a.Id)

六、Linq 实现方式


//比如 Id in (1,2,3)

int[] a=...{1,2,3};
list.Where(x=>a.Contains(x.Id))

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