Sort table td's by ASC/DESC?

mikes02

This is an example out of a book I am working through right now, however, it only allows you to sort by ASC if you click the link once, so if you click username it sorts it by ASC, but I was wondering if it is possible to set it up so that if you clicked the same link again it went to DESC, that way you could switch views while still only using one link?

Thanks for any help that can be provided.

//Default sort order by registration date
	$sort = (isset($_GET['sort'])) ? $_GET['sort'] : 'rd';

//Determine how the results should be ordered
switch($sort)
{
	case 'ln':
		$order_by = 'last_name ASC';
		break;
	case 'fn':
		$order_by = 'first_name ASC';
		break;
	case 'rd':
		$order_by = 'registration_date ASC';
		break;
	case 'un':
		$order_by = 'username ASC';
		break;
	default:
		$order_by = 'registration_date ASC';
		$sort = 'rd';
		break;
}

//Build the table
echo '<table cellspacing="0" cellpadding="5" width="100%">
      <tr>
		<td align="left"><strong><a href="view_users.php?sort=un">Username</a></strong></td>			
	  	<td align="left"><strong><a href="view_users.php?sort=fn">First Name</a></strong></td>			
	  	<td align="left"><strong><a href="view_users.php?sort=ln">Last Name</a></strong></td>
	  	<td align="left"><strong><a href="view_users.php?sort=rd">Date Registered</a></strong></td>
		<td align="left"><strong>Edit</strong></td>
	  	<td align="left"><strong>Delete</strong></td>
	  </tr>';

bretticus

Insert the sort direction into your links also. Use php to get the current direction via the associated $_GET value. If current direction is asc, toggle desc into your link and vise versa.

mikes02

How much of my existing code would have to change to make that work?

bretticus

mikes02;10927205 wrote:
How much of my existing code would have to change to make that work?

As much as it takes to finish the job. Do you need to hire a developer? If you choose to do this yourself, perhaps you can mess with a copy for awhile and ask more specific questions that we can help you with.

mikes02

I should have been more specific, while I appreciate your help, I am far from an expert, I don't need to hire a developer, that's why my code is posted for help.

I was just hoping for a bit more of an explanation of the first method you suggested, based around the code I posted, if that's possible.

johanafm

Add another variable. Default it to ASC if it's not in the GET array. If it does exist and is ASC, you set the href attribute containing it with DESC, otherwise you either leave it out alltogether or you set it to ASC.

mikes02

Thank you. Here is my new code which is working nicely. Please let me know if I should have done anything differently.

	//Default sort order by registration date
	$sort = (isset($_GET['sort'])) ? $_GET['sort'] : 'rd';

//ASC and DESC
$sort_order = 'ASC';
if(isset($_GET['dir']))
{
	if($_GET['dir'] == 'ASC')
	{
		$sort_order = 'DESC';
	} else
	{
		$sort_order = 'ASC';
	}
}

//Determine how the results should be ordered
switch($sort)
{
	case 'ln':
		$order_by = 'last_name';
		break;
	case 'fn':
		$order_by = 'first_name';
		break;
	case 'rd':
		$order_by = 'registration_date';
		break;
	case 'un':
		$order_by = 'username';
		break;
	default:
		$order_by = 'registration_date';
		$sort = 'rd';
		break;
}

//Build the table
echo '<table cellspacing="0" cellpadding="5" width="100%">
      <tr>
		<td align="left"><strong><a href="view_users.php?sort=un&amp;dir='.$sort_order.'">Username</a></strong></td>			
	  	<td align="left"><strong><a href="view_users.php?sort=fn&amp;dir='.$sort_order.'">First Name</a></strong></td>			
	  	<td align="left"><strong><a href="view_users.php?sort=ln&amp;dir='.$sort_order.'">Last Name</a></strong></td>
	  	<td align="left"><strong><a href="view_users.php?sort=rd&amp;dir='.$sort_order.'">Date Registered</a></strong></td>
		<td align="left"><strong>Edit</strong></td>
	  	<td align="left"><strong>Delete</strong></td>
	  </tr>';

mikes02

actually I just noticed that this may not be working exaclty right, for example when the link says "view_users.php?sort=un&dir=ASC" the names are actually displayed in DESC order, and when the link says "view_users.php?sort=un&dir=DESC" the names are actually displayed in ASC order.

Can't seem to figure out where I might be going wrong with this?

bretticus

mikes02;10927227 wrote:
I should have been more specific, while I appreciate your help, I am far from an expert, I don't need to hire a developer, that's why my code is posted for help.

That's wonderful. I just wanted you to ask a better question. After surfing these forums for many years, you wouldn't believe how many people want you to write code for them. I can see you are certainly not one of them, but :

How much of my existing code would have to change to make that work?

...had me wondering for a second there.

You're doing this exactly right. Just use $_GET['dir'] for your database query. $sort_order should only be used for the link (so as to toggle the next click.)

By the way, the code you've shown shows that you are closer to expert than you think.

mikes02

THANK YOU! That did the trick perfectly, I wish I would have caught that, I guess it always helps to have another pair of eyes look it over.

My apologies for coming off like I wanted it done for me, some times I am a bit too vague on forums 🙂. I really appreciate all of your help with this!