从具有多个结果集的存储过程中检索数据

Question

给定SQL Server中有多个select语句的存储过程,有没有办法在调用过程时单独使用这些结果？

例如:

alter procedure dbo.GetSomething
as
begin
    select * from dbo.Person;
    select * from dbo.Car;
end;

在.NET中,如果我调用此proc,我可以使用a SqlDataReader在两个结果集之间移动,这样我就可以轻松检索所有人和汽车.但是在SQL中,当我直接执行proc时,我得到两个结果集.

如果我打电话:

insert @myTempTable
    exec dbo.GetSomething;

然后它会出错,因为列定义不匹配.如果Person和Car有一些机会有相同的列,它将两者连接在一起,@ myTempTable从两个表中获取所有记录,这显然也不好.

我可以定义代表两个结果集的新自定义类型,并创建那些输出参数而不是多个select语句,但我想知道是否有更好的方法 - 将结果拉入临时表或循环结果的某种方式, 或者其他的东西.

编辑

实际上,在仔细观察之后,即使输出表参数也无法解决这个问题 - 它们只是读取,而且在SQL 2012中仍然如此.(连接票据要求添加此项)

Answer 1

String myConnString  = "User ID="username";password="password";Initial Catalog=pubs;Data Source=Server";
SqlConnection myConnection = new SqlConnection(myConnString);
SqlCommand myCommand = new SqlCommand();
SqlDataReader myReader ;

myCommand.CommandType = CommandType.StoredProcedure;
myCommand.Connection = myConnection;
myCommand.CommandText = "MyProc";

try
{
    myConnection.Open();
    myReader = myCommand.ExecuteReader();

    while (myReader.Read())
    {
        //Write logic to process data for the first result.   
        }

    myReader.NextResult();
    while (myReader.Read())
    {
        //Write logic to process data for the second result.
    }
}

Answer 2

在 TSQL 领域，你被困住了。

这是我曾经使用过的一种技巧（有些人可能称之为半黑客）。

/*  START TSQL CODE */

/*  Stored Procedure Definition */

Use Northwind
GO


IF EXISTS 
    (
    SELECT * FROM INFORMATION_SCHEMA.ROUTINES
    WHERE ROUTINE_TYPE = N'PROCEDURE' and ROUTINE_SCHEMA = N'dbo' and ROUTINE_NAME = N'uspOrderDetailsByCustomerId'  
    )
BEGIN
    DROP PROCEDURE [dbo].[uspOrderDetailsByCustomerId]
END


GO

CREATE Procedure dbo.uspOrderDetailsByCustomerId
(
  @CustomerID nchar(5)
, @ResultSetIndicator smallint = 0
)
AS

BEGIN

    SET NOCOUNT ON



    /* ResultSet #1 */

    if (@ResultSetIndicator = 0 OR @ResultSetIndicator = 1)
    BEGIN 
        SELECT 
            c.CustomerID, c.CompanyName /*,c.ContactName,c.ContactTitle,c.[Address],c.City,c.Region,c.PostalCode,c.Country ,c.Phone,c.Fax */
        FROM 
            Customers c 
            JOIN Orders o ON c.CustomerID = o.CustomerID 
        WHERE 
            c.CustomerID = @CustomerID
    END


    /* */
    /* ResultSet #2 */ 

    if (@ResultSetIndicator = 0 OR @ResultSetIndicator = 2)
    BEGIN 

        SELECT o.OrderID,o.CustomerID /* ,o.EmployeeID,o.OrderDate,o.RequiredDate,o.ShippedDate,o.ShipVia ,o.Freight,o.ShipName,o.ShipAddress,o.OrderID,o.CustomerID,o.EmployeeID,o.OrderDate  */
        FROM 
            Orders o 
         WHERE 
            o.CustomerID = @CustomerID
        ORDER BY 
            o.CustomerID , o.OrderID 

    END


    /* */
    /* ResultSet #3 */

    if (@ResultSetIndicator = 0 OR @ResultSetIndicator = 3)
    BEGIN 
         SELECT od.OrderID,od.ProductID /* ,od.UnitPrice,od.Quantity,od.Discount  */
         FROM 
            [Order Details] od 
         WHERE 
            exists (select null from dbo.Orders  innerOrds where innerOrds.OrderID = od.OrderID and innerOrds.CustomerID = @CustomerID )
         ORDER BY 
            od.OrderID 

    END

    SET NOCOUNT OFF


END

GO 
/* Get everything */


exec dbo.uspOrderDetailsByCustomerId 'ALFKI'




    IF OBJECT_ID('tempdb..#TempCustomer') IS NOT NULL
    begin
            drop table #TempCustomer
    end


    CREATE TABLE #TempCustomer
    ( 
      [CustomerID] nchar(5)
    , [CompanyName] nvarchar(40)
    )

INSERT INTO #TempCustomer ( [CustomerID] , [CompanyName])
exec dbo.uspOrderDetailsByCustomerId 'ALFKI' , 1

Select * from #TempCustomer



    IF OBJECT_ID('tempdb..#TempOrders') IS NOT NULL
    begin
            drop table #TempOrders
    end


    CREATE TABLE #TempOrders
    ( 
        OrderID int
      , [CustomerID] nchar(5)

    )

INSERT INTO #TempOrders ( OrderID , [CustomerID] )
exec dbo.uspOrderDetailsByCustomerId 'ALFKI' , 2

Select * from #TempOrders






    IF OBJECT_ID('tempdb..#TempOrderDetails') IS NOT NULL
    begin
            drop table #TempOrderDetails
    end


    CREATE TABLE #TempOrderDetails
    ( 
        OrderID int
      , [ProductID] int

    )

INSERT INTO #TempOrderDetails ( OrderID , [ProductID] )
exec dbo.uspOrderDetailsByCustomerId 'ALFKI' , 3

Select * from #TempOrderDetails


    IF OBJECT_ID('tempdb..#TempOrderDetails') IS NOT NULL
    begin
            drop table #TempOrders
    end


    IF OBJECT_ID('tempdb..#TempOrders') IS NOT NULL
    begin
            drop table #TempOrders
    end



    IF OBJECT_ID('tempdb..#TempCustomer') IS NOT NULL
    begin
            drop table #TempCustomer
    end

Answer 3

虽然 T-SQL 中似乎不支持此功能，但如果您可以选择使用 CLR 存储过程，那么您应该能够使用您首选的 .Net 语言创建一个存储过程，并使用该方法SqlDataReader.NextResult()前进到所需的结果集，然后通过该方法将 SqlDataReader 发送回SqlPipe.Send(SqlDataReader)。您只需将要执行的 SQL 和所需的结果集作为参数传递给该过程。

这将允许您按原样使用过程，而无需修改它以发送回所有或仅一个结果集。

Answer 4

如果没有黑客攻击或重大范式转变，似乎没有好的简单方法可以做到这一点。看起来最好的方法是把原来的 proc 拆分出来，最后得到一个比以前多一个的 proc：

旧方式：

create procedure dbo.GetSomething
as
begin
    select * from dbo.Person;
    select * from dbo.Car;
end;

新方法：

create procedure dbo.GetPeople
as
begin
    select * from dbo.Person;
end;

create procedure dbo.GetCars
as
begin
    select * from dbo.Car;
end;

-- This gives the same result as before
create procedure dbo.GetSomething
as
begin
    exec dbo.GetPeople;
    exec dbo.GetCars;
end;

然后当我在不同的过程中并且需要两个结果集时，我只需要一次调用它们一个。