Question

I am confused.

This is working:

$sql = 'SELECT * FROM TABLE ORDER BY DATEOFUPLOAD DESC'; 
$stmt = $conn->prepare($sql); 
$stmt->execute();

This is not:

$sql = 'SELECT * FROM TABLE ORDER BY DATEOFUPLOAD :orderbydateofupload'; 
$stmt = $conn->prepare($sql); 
$stmt->bindValue(':orderbydateofupload', $orderbydateofupload, PDO::PARAM_STR);  
$stmt->execute();

I have checked and set $orderbydateofupload by $orderbydateofupload='DESC', so it’s definitely not null.

I get an error to the last line ($stmt->execute()):

Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''DESC'' at line 1' in /home/gh6534/public_html/query.php:77 Stack trace: #0 /home/gh6534/public_html/query.php(77): PDOStatement->execute() #1 {main} thrown in /home/gh6534/public_html/query.php on line 77

I also tried to use the column as parameter:

$sort = 'DATEOFUPLOAD';
$sql = 'SELECT * FROM TABLE ORDER BY :sort :orderbydateofupload'; 
$stmt = $conn->prepare($sql); 
$stmt->bindParam(':sort', $sort);
$stmt->bindParam(':orderbydateofupload', $orderbydateofupload);
$stmt->execute(); 

This does not throw an exception, but all items are queried without any sorting. What’s wrong?

Answer 1

Try this

$orderbydateofupload = 'ASC';  //Or DESC

if($orderbydateofupload == 'DESC')
    $sql = 'SELECT * FROM TABLE ORDER BY DATEOFUPLOAD DESC'; 
else
    $sql = 'SELECT * FROM TABLE'