I would recommend running the following code right after your query to see what’s happening: exit( var_dump( $wpdb->last_query ) ); This should print the last query that hit your database. In cases like these, I usually will manually run such a query through phpMyAdmin to see if it runs without errors and to see if … Read more
Thank you everyone for your help! In the end the query below got me the results I desired – which was to show and sort the posts by a custom field of “publication_date” first – sorting by the date, and if there were multiple of the same date (say, 4 marked June 2013), it would … Read more
First, you are using prepare incorrectly. You seem to have $wpdb->update‘s arguments wrapped in $wpdb->prepare like that. That won’t work. In effect, you are passing update a single argument– the output of prepare. Try something simple like the following and you will see why that won’t work: $post_id = 123; $item_stock = 567; var_dump( $wpdb->prepare( … Read more
It’s best practice to always use prepare but the main use of it is to prevent against SQL injection attacks, and since there is no input from the users/visitors or they can’t effect the query then that is not an issue in your current example. But like I said before it’s best practice to use … Read more
Indeed, use get_row() only when you expect to get one result, else you can use get_results()
The $wpdb object has some properties getting set for that: global $wpdb; // Print last SQL query string echo $wpdb->last_query; // Print last SQL query result echo $wpdb->last_result; // Print last SQL query Error echo $wpdb->last_error; Note: First of all you have to set define( ‘SAVEQUERIES’, true ); in your wp-config.php file at root folder … Read more
The $wpdb->esc_like function exists in WordPress because the regular database escaping does not escape % and _ characters. This means you can add them in your arguments to wpdb::prepare() without problem. This is also what I see in the core WordPress code: $wpdb->prepare(” AND $wpdb->usermeta.meta_key = ‘{$wpdb->prefix}capabilities’ AND $wpdb->usermeta.meta_value LIKE %s”, ‘%’ . $this->role . … Read more
Yes it’s possible. The wpdb object can be used to access any database and query any table. Absolutely no need to be WordPress related, which is very interesting. The benefit is the ability to use all the wpdb classes and functions like get_results, etc so that there’s no need to re-invent the wheel. Here’s how: … Read more