SQL Server 存储过程 数组参数 （How to pass an array into a SQL Server stored procedure）

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使用存储过程，如何传递数组参数？

1.分割解析字符串，太麻烦 2.添加Sql Server 自定义类型 **sp_addtype**

问题需求：需要向SP 传递数组类型的参数

select * from Users where ID IN (1,2,3 )

Sql Server 数据类型 并没有数组，但是允许自定义类型，通过 sp_addtype
添加 一个自定义的数据类型，可以允许c# code 向sp传递 一个数组类型的参数
但是不能直接使用 sp_addtype，而是需要结构类型的数据格式，如下：

CREATE TYPE dbo.IDList
AS TABLE
(
ID INT
);
GO
有点像个是一个临时表，一种对象，这里只加了ID
在sp 中可以声明自定义类型的参数

CREATE PROCEDURE [dbo].[DoSomethingWithEmployees]
@IDList AS dbo.IDList readonly

Example

#### 1. First, in your database, create the following two objects

CREATE TYPE dbo.IDList
AS TABLE
(
  ID INT
);
GO

CREATE PROCEDURE [dbo].[DoSomethingWithEmployees]
	@IDList AS  dbo.IDList readonly
	
AS
	 SELECT * FROM [dbo].[Employees] 
	  where ContactId in
	   (  select ID from @IDList )
RETURN 

2. In your C# code

// Obtain your list of ids to send, this is just an example call to a helper utility function
int[] employeeIds = GetEmployeeIds();
DataTable tvp = new DataTable();
tvp.Columns.Add(new DataColumn("ID", typeof(int)));
// populate DataTable from your List here
foreach(var id in employeeIds)
tvp.Rows.Add(id);
using (conn)
{
SqlCommand cmd = new SqlCommand("dbo.DoSomethingWithEmployees", conn);
cmd.CommandType = CommandType.StoredProcedure;
SqlParameter tvparam = cmd.Parameters.AddWithValue("@List", tvp);

// these next lines are important to map the C# DataTable object to the correct SQL User Defined Type
tvparam.SqlDbType = SqlDbType.Structured;
tvparam.TypeName = "dbo.IDList";

// execute query, consume results, etc. here
}