Undefined index

[jeff5656]

I want to sort columns by clicking the name of each column (see code) but

I get this error:

Notice: Undefined index: column_name in C:\wamp\www\mc\displaybundle.php on line 24

 

$query = "SELECT * FROM icu WHERE signoff_status = 'a' ";

$column_name=$_GET['column_name']; /*<--- this is line 24*/

if(isset($column_name) and strlen($column_name)>0){
$query = $query . " order by $column_name ";
} 
else {
$query = $query . " order by rm_loc ";
}


$results = mysql_query ($query) or die (mysql_error());
$num_pts = mysql_num_rows ($results);

 

and here are the column headings starting down at line 41

 

<th width="5%" align="left"><a href='displaybundle.php?column_name=rm_loc'> Room</a></th>
<th width="5%" align="center"><a href='displaybundle.php?column_name=pod'>Pod</a></th>

 

This error GOES AWAY after I sort a column for the first time!

[soak]

Move your isset up a couple of lines:

 

<?php
$column_name=(isset($_GET['column_name']) ? $_GET['column_name'] : ''); /*<--- this is line 24*/

if(strlen($column_name)>0){
$query = $query . " order by $column_name ";
} 

[Kalland]

Hi,

 

Try this:

 

<?php

if(isset($_GET['column_name'])) {
    $column_name = $_GET['column_name'];
} else {
    $column_name = 'order by rm_loc';
}