Wordpress using $_GET in sql query

Question

I am trying to run a "sql query" which needs a post result. I keep getting this error:

Call to a member function get_results() on a non-object in ../includes/functions.php on line 43

Here is my code:

if (isset($_GET['slug'])){
    function get_slug() {
        $slug = 'home';
        return $slug;
    }
} else {
    function get_slug() {
        $sql = "SELECT slug FROM wp_content WHERE slug='".$_GET['slug']."'";
        while ($result = $wpdb->get_results($sql)) {
            $slug = $result['slug'];
            return $slug;
        }
    }   
}

I think that the problem is in the $_GET. I've tried the "wordpress function" get_query_var('slug') instead and still the same error occurs.

Scope issue.. Pass `$wpdb` to your `get_slug($wpdb)` function.. — Shankar Narayana Damodaran, May 12 '14 at 12:13
I know it should be !isset, but it doesn't work if I do that so for now I'm using just isset — Paktwis Homayun, May 12 '14 at 12:27

score 1 · Accepted Answer · answered May 12 '14 at 12:16

1

Here is the modified code. i hope it will work. if not let me know.

if (isset($_GET['slug'])){
    function get_slug() {
        $slug = 'home';
        return $slug;
    }
} else {
    function get_slug() {
        global $wpdb;
        $sql = "SELECT slug FROM wp_content WHERE slug='".$_GET['slug']."'";
        while ($result = $wpdb->get_results($sql)) {
            $slug = $result['slug'];
            return $slug;
        }
    }   
}

answered May 12 '14 at 12:16

Razor Jack

834
4
11

Also, note that you shoudln't be concatenating something that came via $_GET to your SQL stament, that would be prone to SQL Injection. Try escaping or using prepared statements. – Luan Nico May 12 '14 at 12:18
It took me sometime to figure out where it was modified. Using global is considered a [bad practice](http://stackoverflow.com/a/1558073/2513523). You should advice passing the object to the function as mentioned in the above comment. – AyB May 12 '14 at 12:18

score 0 · Answer 2 · answered May 12 '14 at 12:23

0

Its because, $wpdb; is not accessible from inside your function.

If you add a language construct global to $wpdb, you will get this object.

PHP Global Scope

answered May 12 '14 at 12:23

Pupil

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6
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Wordpress using $_GET in sql query

2 Answers2