How do I ORDER BY a variable?

[RichGags]

 

I set up a results page which shows me results from my query...

 

$query_WADAproperties = "SELECT id, pic, address, city, state, submarket, type, class, year, buildingsize, floorsize, space, broker, annualrent FROM properties ORDER BY id ASC";

 

How would I set up the ORDER BY to be a variable so when I click on a column heading on the results page it passes the variable to the php and re-sorts it?

 

I would think that I need to declare a variable that defaults to "id" if nothing is passed to it and put it somewhere .... and make the headings clickable, pointing back to the results.php with a parameter, but have no idea how.

 

Thanks!

Rich

 

[Andy-H]

try this:

 

$order_by = isSet($_GET['order_by']) ? mysql_real_escape_string($_GET['order_by']) : 'id';
$query_WADAproperties = "SELECT id, pic, address, city, state, submarket, type, class, year, buildingsize, floorsize, space, broker, annualrent FROM properties ORDER BY " . $order_by . " ASC";

//blah...

<th><a href="?order_by=pic">Pic</a></th>
<!--- Blahhhh... -->