Using DISTINCT in wp_query

I haven’t tried it myself, but that sounds like something for the posts_distinct or posts_groupby filters:

function search_distinct() {
    return "DISTINCT";
}
add_filter('posts_distinct', 'search_distinct');

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)