在wpdb查询中的wordpressšųūįė字母

I get posts by first letter this way:

$results = $wpdb->get_results(
                "
                SELECT * FROM $wpdb->posts
                WHERE post_title LIKE '$request%'
                AND post_type = 'post'
                AND post_status = 'publish'
                ORDER BY post_title ASC;
                "
            ); 

And I have a problem. If I want to get posts that starts from Ą letter, wordpress gives me posts that starts from A, if Š gives S etc. How can I get posts with strict letter start?

You're most likely using a "Accent Insensitive" database collation. Depending on your exact server set up, you're probably using utf8mb4_unicode_ci or latin1_swedish_ci. You'll most likely need to change that to utf8_YOURREGION_ci or just utf8mb4_bin.

The easiest way to change the DB Collation is directly in phpMyAdmin if you have access to it.