searching by keywords in post’s metas or pagination links problem

Okay. I solved it by myself. i dunno what’s wrong, but it looks like using first case – just doesn’t work. using second case – is a bad idea.

so i began to work with sql and posts_where commands.

first: instead of $wp_query->query_vars['s'] i started to use get_search_query()

second: looks like when sql tries to compare meta_value with value, it asks for %. yes, so in sql code you should write something like:

wp_postmeta.meta_key LIKE \'_entitle\' AND wp_postmeta.meta_value LIKE \'%' . get_search_query() . '%\'

third: because you are using wp_postmeta, you must join its posts ids with ids from wp_posts:

function dasdasd( $join, $query ) {
    global $wpdb;

    if ( is_search() ) {    
        $join = 'INNER JOIN wp_postmeta ON ( wp_posts.ID = wp_postmeta.post_id )';
    }

    return $join;
}
add_filter('posts_join', 'dasdasd', 10, 2 );

and fourth: i dunno why but you must add groupby code:

add_filter( 'posts_groupby', 'adadad', 10, 2 );

function adadad( $groupby, $query ){
    $groupby = 'wp_posts.ID';

    return $groupby;
}

i would like to know what’s wrong with fourth step and why groupby’s existing is so important for search query. thank you.