Linq 如何实现 in 与 not in

Posted 2021-02-07 wangfuyou

T-SQL的IN：

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

T-SQL的NOT IN：

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

Or

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

LINQ的IN：

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

LINQ的IN解析成SQL：

SELECT [t0].[ProductID], [t0].[ProductName], [t0].[SupplierID], [t0].[CategoryID], [t0].[QuantityPerUnit], [t0].[UnitPrice], [t0].[UnitsInStock], [t0].[UnitsOnOrder], [t0].[ReorderLevel], [t0].[Discontinued] 
FROM [dbo].[Products]AS [t0]
WHERE [t0].[CategoryID] IN (@p0, @p1)

LINQ的NOT IN：

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

LINQ的NOT IN解析成SQL：

SELECT [t0].[ProductID], [t0].[ProductName], [t0].[SupplierID], [t0].[CategoryID], [t0].[QuantityPerUnit], [t0].[UnitPrice], [t0].[UnitsInStock], [t0].[UnitsOnOrder], [t0].[ReorderLevel], [t0].[Discontinued] 
FROM [dbo].[Products]AS [t0]
WHERE NOT [t0].[CategoryID] IN (@p0, @p1)

 

转：https://blog.csdn.net/zhangyumei/article/details/5620363