Using multiple selection array in table to order data

cadams

I have a form that has a multiple select choice, like this:

<form method="post" action="display.php"

<select multiple name="selectsort[]">
<option value="code">Code</option>
<option value="amount">Amount</option>
<option value="dateammended">Date Ammended</option>
<option value="expreviewdate">Expiration/Review Date</option>
<option value="effectivedate">Effective Date</option>
<option value="expired">Expired</option>
<option value="team">Issuing Team</option>
<option value="originate">OSL Originate</option>
</select>
</form>

The display.php file runs a query that sorts the results based on the selection (sometimes multiple) made in the form. The display.php file looks something like this:

$selectsort = $_POST['selectsort'];

if( isset( $POST['selectsort'] )) {
$query = "SELECT * FROM contracts ORDER BY '{$POST['selectsort']}' DESC";

}

$result = mysql_query($query);

I then echo the information in a table. I get results, but it doesn't pay attention to multiple selections. It only orders by the last selection made.

I can echo out the various selections and can see that the select part is working.

echo "$selectsort[0] , $selectsort[1] , $selectsort[2], ........"

How can use the selectsort[] array to order by the multiple selections?

Roger_Ramjet

You have to build the order clause dynamically. The big question is the order of the sort options?

$sql = "SELECT * FROM contracts";
if (isset($_POST['selectsort'])) {
  $sort = implode("," , $_POST['selectsort']);
  $sql .= " ORDER BY " . $sort . " DESC";
}

cadams

Thanks for your reply. I was just starting to investigate the use of 'implode'. I still can't get it to work quite right. It doesn't seem to pay attention to the 'ORDER BY', as I can't even get it to order by one choice.

As for the order, I assume that something like this would work:

"ORDER BY (field 1/field2) ASC, field 3 ASC"

It seems that using this with the multiple selection could get a little hairy.

If I can even get this to work with the first selection being ordered first (which I assume is the default), I will be a big step ahead.

I am a little confused about this part:

'$sql .= '

I understand what comes after it, but why is the $sql variable being set, for use possibly at a later time?

Roger_Ramjet

$sql is the query you are constructing, it could as easily be called $query, or $meatloaf, it is just my personal habit.

.= is shorthand concatenation, same as $query = $query . $sort

Your thoughts on what would work for ORDER BY are wrong so read the manual.

Actually, looking at your post again I see that you want to do this with the implode

  $sort = implode("DESC," , $_POST['selectsort']);

If your query is not working the FIRST thing to do is to echo it too see what you have constructed.