Assign Var To Textbox From SQL Query

URLURLOn page load there is a variable called "id" it has already got the value (say 7170)

I have a query in a function that executes a dataset, the query is "select Col1, Col2 from persons where id = " & id

Therefore, on page load - how do I call the function. Assign the value of Col1 to textbox1 and the value of Col2 to textbox2.

In the text box I would use <%=var %>

But how do I assign the result of the query to the variable?

Would it be worth using a datareader instead?