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1. kmeiding
   Member
   Posted 7 months ago #

   I am writing a plugin for a website I'm working on and am having trouble accessing the database. This code is supposed to retrieve a comment from a table I created with the name wp_motivational_comments. I just did the table by hand because I was having trouble and this plugin is so specific it most likely will never be used on any site.

   Here's the code to select from the database.

   global $wpdb;
   
   	$sql = "SELECT comment FROM " . $wpdb->prefix . "motivational_comments WHERE id = " . $_SESSION['comments'][$month - 1];
   	echo $sql;
   	$this_months_comment = $wpdb->get_var($sql);

   I get this error when I get to this page;

   Fatal error: Call to a member function get_var() on a non-object in /Applications/XAMPP/xamppfiles/htdocs/wordpress/wp-content/plugins/EMSMSimulator/results.php on line 55

   When I printed out the sql statement, it was:

   SELECT comment FROM motivational_comments WHERE id = 19

   This is the first time I have worked with PHP or WordPress plugins and I've tried to do some research and can't find a solution to my problem.

   If I am understanding things correctly, the $wpdb->prefix should put the wp_ prefix on the table name but it is not working the way I think it should.

   Can anyone help?

2. Big Bagel
   Member
   Posted 7 months ago #

   $wpdb is empty for whatever reason; you can check with var_dump( $wpdb );.

   Is results.php being included from your main plugin file (if it's not the main file), or are you accessing it directly?

3. kmeiding
   Member
   Posted 7 months ago #

   results.php is the form action from the previous page.

4. Big Bagel
   Member
   Posted 7 months ago #

   WordPress doesn't get loaded when results.php is accessed directly. Thus, a nonexistent $wpdb. To load up WordPress so you can use its global variables and functions, try including/requiring wp-load.php beforehand. Something like:

   require( '/path/to/wp-load.php' );

5. kmeiding
   Member
   Posted 7 months ago #

   Thank you! That fixed it.

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