Use AdventureWorks;
Go
 
Create Procedure dbo.LastOrderGet_sp
As
Set NoCount On;
Begin
 
    Select Max(SalesOrderID) As 'LastSalesOrderID'
    From AdventureWorks.Sales.SalesOrderHeader With (NoLock)
 
    Set NoCount Off;
    Return 0;
End
Go
 
Create Procedure dbo.ProcessLastOrder_sp
    @LastOrderID int
As
Set NoCount On;
Begin
 
    Select SalesOrderDetailID
        , ProductID
        , OrderQty
        , LineTotal
    From AdventureWorks.Sales.SalesOrderDetail With (NoLock)
    Where SalesOrderID = @LastOrderID;
 
    Set NoCount Off;
    Return 0;
End
Go
 
Create Table dbo.testStage
(
      SalesOrderDetailID    int
    , ProductId             int
    , OrderQty              smallint
    , LineTotal             numeric
);
Go

Now for the fun stuff!

(Please note, I'm assuming some basic understanding of SSIS, so I'm skipping the "how to create a project", etc. stuff and just going to the pertinent parts).

Inside BIDS (Business Intelligence Development Studio), create a new SSIS project and call it what you will. If your Variable window is not already open, open it now by going to View --> Other Windows --> Variables.

Open Variables Window

Now let's create a variable. To do this, click on the little icon in the upper left-hand corner of the Variables window. Name the variable LastSalesOrderID.

Create a variable

After you create the variable, you should now see it in the Variables window. Make sure the scope of the variable is the name of your project, which is "Blog" in my case (for obvious reasons); this means the variable is defined at the package scope. Once you've confirmed that the variable exists, create an Execute SQL task.

(Variables in SSIS, like in other programming languages, can have different scopes. For instance, a package scope means the variable can be accessed anywhere within the package, but a variable with a Data Flow scope can only be accessed within the specified Data Flow task.)

Create Execute SQL Task

Double-click on your Execute SQL Task and configure with the following values:

• Set "Result Set" to Single Row.
• Set your Connection to your appropriate data source.
• Set your SQL Statement to: Execute AdventureWorks.dbo.LastOrderGet_sp;

Set up your Execute SQL Task

Now click on "Result Set" and click on "Add." You'll want to put the name of the column that's returned by the proc in the "Result Name" column; in our case, that'll be LastSalesOrderID. Click on the Variable Name column and scroll down until you find the appropriate one (User::LastSalesOrderID).

Mapping the results to a variable

Go ahead and add a Data Flow task to the designer surface. We don't need to use a Data Flow task here -- for example, we could use another Execute SQL task instead -- but this will help demonstrate one way to use variables.

Add Data Flow Task

Double-click on the Data Flow task and add an OLE DB Source, then double-click on it to open up the properties. Enter the following text in the "SQL Command text" window:
Execute AdventureWorks.dbo.ProcessLastOrder_sp ?
The question mark (?) tells SSIS to expect a parameter.

Edit OLE DB Source

Now click on the Parameters button on the left. This is where we map our variable to our parameter. For the "Parameters" value, enter @LastOrderID (the parameter the stored procedure is expecting). In the "Variables" column, click on the drop-down and navigate to the User::LastSalesOrderID variable.

Map Variables to Parameters

Finally, set up an OLE DB Destination, and configure the OLE DB Source to load into the testStage table.

Configure OLE DB Destination

At this point, you should be able to successfully execute your package. Upon successful execution, the testStage table will return the following results:

Select * From testStage;
 
SalesOrderDetailID ProductId   OrderQty LineTotal
------------------ ----------- -------- ------------------
121315             878         1        21
121316             879         1        159
121317             712         1        8

That's all for now. Hopefully this gives you an idea of how easy and useful it is to work with variables in SSIS.