Merge duplicate title in diffrent categories

It’s one single post filed under more than 1 category.

yes, i can edit single post, but i have to much posts, and people who created posts, don’t thinking about it. To moderate – really hard

i founded code in wp-include, post.php lines

if ( !in_array( $post_status, array( ‘draft’, ‘pending’ ) ) ) {
$post_name_check = $wpdb->get_var($wpdb->prepare(“SELECT post_name FROM $wpdb->posts WHERE post_name = %s AND post_type = %s AND ID != %d AND post_parent = %d LIMIT 1”, $post_name, $post_type, $post_ID, $post_parent));

if ($post_name_check || in_array($post_name, $wp_rewrite->feeds) ) {
$suffix = 2;
do {
$alt_post_name = substr($post_name, 0, 200-(strlen($suffix)+1)). “-$suffix”;
$post_name_check = $wpdb->get_var($wpdb->prepare(“SELECT post_name FROM $wpdb->posts WHERE post_name = %s AND post_type = %s AND ID != %d AND post_parent = %d LIMIT 1”, $alt_post_name, $post_type, $post_ID, $post_parent));
$suffix++;
} while ($post_name_check);
$post_name = $alt_post_name;
}
}

but how in checking to fix duplicate?

There are no duplicates. You have a number of single posts filed under more than 1 category. So they will be listed on more than 1 category page.

I’m using WP-o-Matic and my feed campaign is assigned to 2 different categories, so that in the result I get 2 equal posts in 2 categories, but I need to have 1 post in 2 categories