Hi,
I suggest the following steps to you.
-> Add ASP.NET button instead of HTML button, since there is no post back facility in HTML button.
-> Add custom attribute "tag" to that button.
<asp:Button ID ="ID1" runat="server" tag="test" ..
the value for tag is your wish, based on what you want to differentiate the buttons.
-> In server side event, handle the event as you are doing currently based on the button.
-> Even if many buttons, you handle in single event function only.
-> in the event function identify the button, based on the tag value.
string tag = ((Button)sender).Attributes["tag"].ToString();
-> execute the select statement and display the details in the screen.
hope it helps.