Prepared SQL Statements and Performance

The Informix SQL reference manuals state that using a prepared SQL statement together with an Execute statement makes the SQL more efficient. If this is true, then which example is more efficient: declare cursor1 cursor for select col1, col2, col3 from tablea where col1 = col5 or let l_SQL = "select col1, col2, col3 ", "from tablea ", "where col1 = col5" prepare SQL_stmt from l_SQL declare cursor1 cursor for SQL_stmt Note that I did not use an execute in this example. Which of the aboove examples yields the best performance and why?