How do I iterate through the rows in a gridview and add a column to a table in a SQL Server DB

I have a gridview with multiple rows and multiple columns.  I want to iterate through all of the rows adding a specific column from each row to a SQL server table also (with only one field). I think this should be straight forward, but when I googled this I could not find any VB code that will do this.  The data in the gridview is a subset of the gridview's data source, so I cannot use the data source, I need to iterate through the gridview.    How do I do this?  How do I select the specific column in the database?  Can someone suggest VB code that will accomplish this?  I appreciate any advise you choose to offer - thanks..................Phil Hoop