PHP Function Returning True When It Should Return False

Question

I'm having trouble with a PHP function for a very small WYSIWIG-like app. The following function determines whether a user owns a page. It has print statement for debugging.

function is_owned($sitename, $page_id)
{
    $output = false;

    $result = count(single_row_query(sprintf("SELECT page_id FROM pages WHERE sitename='%s' AND page_id='%s';", addslashes($sitename), addslashes(strval($page_id)))));

    print $result;

    if ($result != 0)
        {$output = true; }

    return $output;
}

The following is the output of the page I'm using to debug the function.

SELECT sitename FROM session WHERE uid='l8rc8ssri8qr65lqvtfp174s91'
SELECT page_id FROM pages WHERE sitename='Test' AND page_id='132432';
Result: 0
The function has returned true.

As you can see, the value of $result is 0, but the function still returned true. The SQL statements are included, though the problem doesn't seem to lie there.

The following function is called be the is_owned(), but is not likely to be relevant, as it seems to be functional.

function single_row_query($query)
{
    $database_connection = open_connection();

    $result = mysql_query($query);

    $output = mysql_fetch_array($result);

    $output = $output[0];

    mysql_free_result($result);
    mysql_close($database_connection);

    return $output;
}

Thank you very much for your assistance.

Edit: Additionally, this is the output of the test page when it is supposed to return true:

! SELECT sitename FROM session WHERE uid='l8rc8ssri8qr65lqvtfp174s91' !
! SELECT page_id FROM pages WHERE sitename='Test' AND page_id='7'; !
Result: 1
The function has returned true.

Could you include the code that prints 'The function has returned true'? Maybe that's the problem. — Jakob Egger
– Jakob Egger, Commented Mar 2, 2012 at 7:14
Oh, derp. You're completely correct, I forgot to put a $ on a variable. Sorry for the trivial question. — Max Bond
– Max Bond, Commented Mar 2, 2012 at 7:20

Farray · Accepted Answer · 2012-03-02 07:56:55Z

2

Your problem was the result of a typo, but here is why the other answers are completely wrong.

PHP count always returns an int. Specifically:

Returns the number of elements in var. If var is not an array or an object with implemented Countable interface, 1 will be returned. There is one exception, if var is NULL, 0 will be returned.

Regardless of what else happens in the single_row_query function, count will return an int. At that point, there is no practical difference between $result != 0 and $result !== 0 or the other posited issues. Strong type comparison doesn't matter because you will necessarily be comparing an int value with an int value.

At that point, your function was sound and your problem must reside somewhere else.

answered Mar 2, 2012 at 7:56

Farray

8,5883 gold badges35 silver badges37 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

MNe · Accepted Answer · 2012-03-02 07:11:42Z

-1

Try:

if ($result !== 0) {
    $output = true;
}

answered Mar 2, 2012 at 7:11

MNe

71 bronze badge

1 Comment

Max Bond Over a year ago

It is still returning true when $result is 0.

sam_13 · Accepted Answer · 2012-03-02 07:27:03Z

-1

Try this condition [UPDATED]

if(!empty($result))
{$output = true; }

edited Mar 2, 2012 at 7:27

answered Mar 2, 2012 at 7:15

sam_13

5323 silver badges9 bronze badges

1 Comment

Max Bond Over a year ago

The function doesn't have access to the SQL result, its handled by another function. The $result variable is the first (and only) row of the SQL result.

rdo · Accepted Answer · 2012-03-02 07:54:16Z

-2

make var_dump($result) instead of print $result in cause of var_dump prints type of variable (print converts variable to string), so you will see real value.
use if ($result !== 0) for strong type comparison.

answered Mar 2, 2012 at 7:54

rdo

4,0026 gold badges39 silver badges52 bronze badges

Collectives™ on Stack Overflow

PHP Function Returning True When It Should Return False

4 Answers 4

Comments

1 Comment

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Comments

1 Comment

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related