Question

Okay, so I have the weirdest problem right now. My code is fine! It works PERFECTLY as I want and expect it to, which is a major shock to me, because every time I go to do MySQL I get endless problems that I can never find a solution to.

But today, everything works perfectly. So what’s the problem? The problem is that when I try to wrap my code in a function, it just… stops working! I have error checking after every step and it works fine when in it’s own file and lines. But I need to put it in a function so I can add parameters (hence the “extraQuery” variable), and “return” it so that I can access it from a separate file.

Here is my base code:

$link = mysql_connect($db_host, $db_user, $db_pass) or die ("Unable to connect: " . mysql_error());
mysql_select_db($db_name, $link) or die("Couldn't connect to database: " . mysql_error());

$extraQuery = "";
$result = mysql_query("SELECT * FROM things " . $extraQuery . " ORDER BY RAND() LIMIT 1", $link);

$row = mysql_fetch_array($result, MYSQL_ASSOC);
mysql_close($link);
echo($row['content']);

As I said, it works completely fine as that is. But when I do this….

function getResult(){
    $link = mysql_connect($db_host, $db_user, $db_pass) or die ("Unable to connect: " . mysql_error());
    mysql_select_db($db_name, $link) or die("Couldn't connect to database: " . mysql_error());

    $extraQuery = "";
    $result = mysql_query("SELECT * FROM things " . $extraQuery . " ORDER BY RAND() LIMIT 1", $link);

    $row = mysql_fetch_array($result, MYSQL_ASSOC);
    mysql_close($link);
    echo($row['content']);
}
getResult();

..It stops working at the second line, telling me “No database selected”. But as you can see, I am explicitly selecting a database that DOES exist and otherwise works when it’s not in a function.
And just to stress this, it is NOT my user permissions, nor is it the name of the database; because it works perfectly when outside of the function.

Any possible aid would be greatly appreciated.

Answer 1

Due to variable scope your database variables are not available inside of the function. You need to pass it as an argument for getResult() to have access to it:

function getResult($db_host, $db_user, $db_pass, $db_name, $extraQuery){
    $link = mysql_connect($db_host, $db_user, $db_pass) or die ("Unable to connect: " . mysql_error());
    mysql_select_db($db_name, $link) or die("Couldn't connect to database: " . mysql_error());

    $extraQuery = "";
    $result = mysql_query("SELECT * FROM things " . $extraQuery . " ORDER BY RAND() LIMIT 1", $link);

    $row = mysql_fetch_array($result, MYSQL_ASSOC);
    mysql_close($link);
    echo($row['content']);
}
getResult();