Passing variable in function

This is for a sorting script. I want to order my posts by votes. I'm using an if-statement in a function to check what order by was selected and display posts according to that.

The following function inserts data in my query.

function vote_orderby( $orderby )
{
  global $vote_sort;

  if( $vote_sort == "most_voted") {
     // order by most votes
     return "votes DESC"; //inserts into query
  }

  // return default order by if no votes
  return $orderby;
}

HTML

$vote_so开发者_如何学Pythonrt = "most_voted"; //should be picked up by function

..function
..loop

I want to generate,

$query = "SELECT * FROM posts ORDER BY votes DESC";

But posts are ordered by date. It works however without the if-statement, this ensures that I have no MYSQL errors.

How is it possible to pass the $vote_sort value into the function?

Note: I'm aware of the SQL injection risk, I will filter everything soon.

To answer your comment and expand on Michael's solution above, here is what you might want to do...

 function vote_orderby($orderby) {  
    switch($orderby) {
       // Sort by most votes
       case 'most_voted': $sort = 'votes DESC'; break;
       // Sort by least votes
       case 'least_voted': $sort = 'votes ASC'; break;
       // Default to most votes if does not match any other option
       default: $sort = 'votes DESC'; break;
    }
    return $sort; // Return query statement
 }

Then your query statement would be such as...

$sortby = $_GET['sort']; // However you want to get the way to sort
// If $sortby is empty, it will default to most_voted via function
$order = vote_orderby($sortby);
$query = "SELECT * FROM posts ORDER BY ".$order;

This is more of a permanent way of coding the system and prevent people to inject your MYSQL query and minor mistakes will not result in the future.

I have coded many similar systems in the past and this is one of the best ways to go.

You probably want something like this:

 function vote_orderby( $orderby='most_voted' ) {  
   if( $orderby == "most_voted") {    
      // order by most votes  
      return "votes DESC"; //inserts into query  
   }  

  // return default order by if no votes  
 return $orderby;  
 }

In your query you want something simular to this

// this will give you the default;
$orderby = vote_orderby();
$query = 'SELECT * FROM posts ORDER BY ' . $orderby;

Or

// this will give you the name;
$orderby = vote_orderby('NAME DESC');
$query = 'SELECT * FROM posts ORDER BY ' . $orderby;

But you might just want to set a variable to the sort method and pass that into your query. Doing this in a function is a bit of a overkill or you could just add the whole query inthere and return the right one.