update table1 t1 join table2 t2 on t2.field = t1.field set t1.field1 = t2.matchingfield where t1.whatever = t2.whatever …
MySQL copy table data to a new table
CREATE TABLE backup_table LIKE existing_table; INSERT backup_table SELECT * FROM existing_table; …
Get all WordPress user emails
$users = get_users(); foreach ( $users as $user ) { $email = $user->user_email; } …
Find duplicates values in a MySQL table
SELECT col, COUNT(col) FROM table_name GROUP BY col HAVING COUNT(col) > 1; …
Delete orphaned post meta in WordPress database
DELETE pm FROM wp_postmeta pm LEFT JOIN wp_posts wp ON wp.ID = pm.post_id WHERE wp.ID IS NULL …
Simple plugin header
Error log file by date with hash
// Get stored hashes. $error_log_hashes = get_option( 'error_log_hashes' ); // Get today's date. $date = date('Y-m-d'); // Check if …
Error log files by date name
ini_set( 'error_log', WP_CONTENT_DIR . '/debug-' . date('Y-m-d') . '.log' ); …
Run WordPress in debug mode without access to wp-config
add_action( 'template_redirect', 'my_enable_debug_mode' ); function my_enable_debug_mode() { // Turn on error reporting. …