Hi Hazel,

Refer below code.

Database

I have made use of the following table Customers with the schema as follows.

You can download the database table SQL by clicking the download link below.

Download SQL file

Code

C#

protected void Button1_Click(object sender, EventArgs e)
{
    string[] nm = GetIds().ToArray();
    foreach (string name in nm)
    {
        string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
        using (SqlConnection con = new SqlConnection(constr))
        {
            using (SqlCommand cmd = new SqlCommand("INSERT INTO Names(Name) VALUES(@Name)"))
            {
                cmd.Connection = con;
                cmd.Parameters.AddWithValue("@Name", name);
                con.Open();
                cmd.ExecuteNonQuery();
                con.Close();
            }
        }
    }
}

private List<string> GetIds()
{
    List<string> ids = new List<string>();
    string conString = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    string query = "SELECT Name FROM Customers";
    using (SqlConnection con = new SqlConnection(conString))
    {
        SqlCommand cmd = new SqlCommand(query);
        con.Open();
        SqlDataReader sdr = cmd.ExecuteReader();
        while (sdr.Read())
        {
            ids.Add(sdr["Name"].ToString());
        }
        con.Close();
    }
    return ids;
}

VB.Net

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs)
    Dim nm As String() = GetIds().ToArray() 
    For Each name As String In nm
        Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString 
        Using con As SqlConnection = New SqlConnection(constr) 
            Using cmd As SqlCommand = New SqlCommand("INSERT INTO Names(Name) VALUES(@Name)")
                cmd.Connection = con
                cmd.Parameters.AddWithValue("@Name", name)
                con.Open()
                cmd.ExecuteNonQuery()
                con.Close()
            End Using
        End Using
    Next
End Sub
 
Private Function GetIds() As List(Of String)
    Dim ids As List(Of String) = New List(Of String)()
    Dim conString As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
    Dim query As String = "SELECT Name FROM Customers" 
    Using con As SqlConnection = New SqlConnection(conString)
        Dim cmd As SqlCommand = New SqlCommand(query)
        con.Open()
        Dim sdr As SqlDataReader = cmd.ExecuteReader() 
        While sdr.Read()
            ids.Add(sdr("Name").ToString())
        End While 
        con.Close()
    End Using
 
    Return ids
End Function