Problems with displaying mysql results

Question

<?php  

include('../Adress/includes/mysql_connection_recepti.php');

if (isset($_POST['username'])){

$conn = dbConnect($_POST['username']);


$city=$_POST['city'];

$sql= 'SELECT * FROM adress_table WHERE city="'.$city.'"';

$result=mysql_query($sql);

$numRows=mysql_num_rows($result);

?>

<p><?php echo $numRows; ?> records is found.</p>

<table>
<tr>
<th>Number</th>
<th>Name</th>
<th>Last Name</th>
<th>City</th>
<th>Country</th>
<th>Date</th>
</tr>

<?php 
$n=0;

while($row = mysql_fetch_assoc($result)){
//print_r($row);

$n++;

?>

<tr>
<td><?php echo $n . ".";?></td>
<td><?php echo $row['name'] ?></td>
<td><?php echo $row['last_name'] ?></td>
<td><?php echo $row['city'];?></td>
<td><?php echo $row['country'] ?></td>
<td><?php echo $row['date'] ?></td>
</tr>

<?php }?>

</table>

<?php }?>
</body>
<body>

<form action="" method="post">
<input type="text" id="username" name="username"/>


<select name="city">
<option value="new_york">New York</option>
<option value="london">London</option>
<option value="belgrade">Belgrade</option>
<option value="zagreb">Zagreb</option>
<option value="moscow">Moscow</option>

<input type="submit" value="Find">
</select>
</body>

As you can see, my sql statement tells that every column has to be displayed when city="'.$city.'", and that is completely ok. But when I try to display some particular column(s), not all (*), for example

$sql= 'SELECT name,last_name FROM adress_table WHERE city="'.$city.'"';

then error emerges, bacause

 <td><?php echo $row['city'];?></td>
 <td><?php echo $row['country'] ?></td>
 <td><?php echo $row['date'] ?></td>

are not defined. In order to fix this I put @ sign

 <td><?php @ echo $row['city'];?></td>
 <td><?php @ echo $row['country'] ?></td>
 <td><?php @ echo $row['date'] ?></td>

to cover up error messages and I cat tell you that everything looks perfectly all right, but I don't know is it good practice. What should I do? Thanks.

The usual way to prevent this is checking each variable with php.net/isset but why are you trying to output columns that you're not selecting in the first place? I don't see how that would ever make sense. — Pekka
– Pekka, Commented Jun 30, 2013 at 8:48
Because I imagine that in sql statement name of columns that are to be displayed could be dynamically chosen by user, but I didn't show that in this code. — natttan
– natttan, Commented Jun 30, 2013 at 9:05
Can't you limit the displaying of columns using the same system you use to limit the querying? — Pekka
– Pekka, Commented Jun 30, 2013 at 9:12

Paul Moldovan · Accepted Answer · 2013-06-30 08:51:34Z

2

You can just use an if to check if there is something in there or not:

<?php echo isset($row["city"]) ? $row["city"] : "" ?>

answered Jun 30, 2013 at 8:51

Paul Moldovan

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3 Comments

Nitesh Over a year ago

Cant believe we added same answer :)

Paul Moldovan Over a year ago

Yeah. Well I think he got the idea ^_^

natttan Over a year ago

Thanks, I think I did it in the first place, it seems obvious to me to try that, but something went wrong. I'll try it again, thanks!

Nitesh · Accepted Answer · 2013-06-30 08:52:08Z

1

You are trying to display a column that is not present in your SQL query. YOu can use something like -

<?php echo isset($row["city"]) ? $row["city"] : "" ?>

answered Jun 30, 2013 at 8:52

Nitesh

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