Functions with sql queries

[zimmo]

I am learning how to use functions, and they are a great. I am unsure of how to perform an sql query in a function. It is checking to see if a username is taken. Can this be done with a function?

 

Here is the query, but it is failing when called.

 

<?
function validUsername($username)
{
  $sql = "SELECT * FROM tableA WHERE username = '$_POST[username]' "; 
  $sql_result = mysql_query($sql); 

if (mysql_num_rows($sql_result) !=0)
{
	$isValid = true;
}
else
{
	$isValid = false;
}
return $isValid;
} 
?>

[grim1208]

try defining username outside of the function. making code look like this

 

<?
$username = $_POST['username'];  // defines username
validUsername($username);   // this calls the function

function validUsername($username)
{  
  $sql = "SELECT * FROM tableA WHERE username = '$_POST[username]' ";   
  $sql_result = mysql_query($sql);  	
  
  if (mysql_num_rows($sql_result) !=0)	
  {		
    $isValid = true;	
  }	
  else	
  {		
    $isValid = false;	
  }	
  
  return $isValid;
} 
?>

[oni-kun]

Please do not use short tags, It is sloppy and not even a PHP delimiter.

[zimmo]

Please do not use short tags, It is sloppy and not even a PHP delimiter.

 

Hi Can you tell me where? I have not heard of this, still learning. Thanks

[grim1208]

<? = short tag ....

<?php = correct way, even though <? is not incorrect

[Re321]

Mhmm oni-kun is right.

[zimmo]

Doh... sorry, yes I just missed that. I normally do us php not just the ?. Thanks for pointing that out.

 

Sorry I forgot to add about the function. The function I posted up, is actually held within an external file and called from the header using an include.

 

The actual page that calls the form has the following code, but it does not work, it gives me no error, but it does not actually perform the sql query? it just tries to insert a duplicate.

 

Here is the code calling the function:

 

	if ( empty($username) ) {
	$error['username_error'] = '<div class="formerror">Please enter your username</div>';
	}
	elseif (!validUsername ($username) ) {
	$error['username_error'] = '<div class="formerror">Username taken</div>';
	}

[oni-kun]

Try:

$sql_result = mysql_query($sql) or die(mysql_error());

[zimmo]

Oni its not giving me any errors now, but it is stating that the username is taken, even though I have emptied the tables so nothing is there now, it just wont register now?

[zimmo]

I had the isvalid the wrong way around, doh!! just realised and its working great now. Could you tell me oni why changing to that query worked?