Im not Sure of What your doing.....
are u client side, server side, in a Stored Proc

if client side , I generallly use the schema of the table
to create my 2nd table and add the columns required

below is a smal sample using datareader -> directly into a table
/// <summary>

/// Ads some Functionality

/// does not close reader here ..mite call readToTable many times for one
Read into multiple tables

/// from multiple selects from one Stored Proc

/// user of this code must close the reader

/// </summary>

public static class MySqlReader

{

/// <summary>

/// Reades the SqlReader Result Set into A Datatable

/// Provide a New DataTable or Existing Datatable

/// this Routing only Adds Columns on a New DataTable

/// </summary>

/// <param name="Reader"></param>

/// <param name="UserTable"></param>

/// <returns></returns>

public static int ReadToTable(SqlDataReader Reader, DataTable UserTable)

{

//dont Add columns if they Already Exist only if this incomming usertable is
a empty Datatableclass

if (UserTable.Columns.Count == 0)

{

DataTable Schema = Reader.GetSchemaTable();

DataRow Row;

DataColumn Col;

//define the Columns and Add to User Table

for (int x = 0; x < Schema.Rows.Count; x++)

{

Row = Schema.Rows[x];

string ColumnName = (string)Row["ColumnName"];

Col = new DataColumn(ColumnName, (Type)Row["DataType"]);

UserTable.Columns.Add(Col);

}

}

object[] ColumnValues = new Object[Reader.FieldCount];

while (Reader.Read())

{

Reader.GetValues(ColumnValues);

UserTable.LoadDataRow(ColumnValues, true);

}

return UserTable.Rows.Count;

}

/// <summary>

/// Creates New Table When Called

/// </summary>

/// <param name="Reader"></param>

/// <returns></returns>

public static DataTable ReadToTable(SqlDataReader Reader)

{

// Creates a New Table Each Time...lets say this is used by a service

// if Result Set changes we need a new table

DataTable NewTable = new DataTable();

DataTable Schema = Reader.GetSchemaTable();

DataRow Row;

DataColumn Col;

//define the Columns and Add to User Table

for (int x = 0; x < Schema.Rows.Count; x++)

{

Row = Schema.Rows[x];

string ColumnName = (string)Row["ColumnName"];

Col = new DataColumn(ColumnName, (Type)Row["DataType"]);

NewTable.Columns.Add(Col);

}

object[] ColumnValues = new Object[Reader.FieldCount];

while (Reader.Read())

{

Reader.GetValues(ColumnValues);

NewTable.LoadDataRow(ColumnValues, true);

}

return NewTable;

}

/// <summary>

/// Creates and Defines columns for a new DataTable from Table Schema

/// Returns new Table;

/// </summary>

/// <param name="Reader"></param>

/// <returns></returns>

public static DataTable CreateTable(SqlDataReader Reader)

{

DataTable Schema = Reader.GetSchemaTable();

DataTable NewTable = new DataTable();

DataColumn Col = new DataColumn();

for (int x = 0; x < Schema.Rows.Count; x++)

{

DataRow row = Schema.Rows[x];

string ColumnName = (string)row["ColumnName"];

Col = new DataColumn(ColumnName, (Type)row["DataType"]);

NewTable.Columns.Add(Col);

}

return NewTable;

}

}