更改代码以将mySQL链接到函数中

Question

I'm new to php. I have this piece of code:

<?php 
if (!isset($_GET['id'])) {
    die("missing query parameter");
}
$id = intval($_GET['id']);
if ($id === '') {
    die("Invalid query parameter");
}

$db = mysql_connect("localhost", "root", "usbw");
$sdb = mysql_select_db("test", $db);
$sql = "SELECT * FROM config WHERE id=$id";
$mq = mysql_query($sql) or die("not working query");
$row = mysql_fetch_array($mq);
?>

And from this code, I want to make a function, but how? What I'm trying to do is linking my MySQL database to my PHP code, and I also try to use the GET[id] to auto change my page if a change my id.

This piece of code does work, but I want to change it into a function. But I don't know how to start.

Answer 1

Here's an example of a function around your query, mind you it's just an example, as there are many improvements to make.
Such as not using the mysql_* api and moving towards PDO or mysqli_*

But it should be enough to get you started

<?php

// your if logic stays unchanged

$db=mysql_connect("localhost","root","usbw");
$sdb=mysql_select_db("test",$db);


function getConfig($id,$db){

    $sql="SELECT * FROM config WHERE id=$id";
    $mq=mysql_query($sql);

    if ($mq) {
        return mysql_fetch_array($mq);
    }
    else {
        return false;
    }

}

$results = getConfig($id,$db);

if ($results==false) {
    print "the query failed";
}
else var_dump($results);