How to filter custom post type archive by meta value

Like Bainternet said in comments, you’ll need to mess with add_query_var as well as add_rewrite_rule. We usually do something similar to: global $wp; $wp->add_query_var( ‘some_var’ ); add_rewrite_rule( ‘some/path/([^/]+)/?$’, ‘index.php?some_var=$matches[1]’ ); See this WordPress Trac ticket, as well as documentation on add_query_var and add_rewrite_rule

How can I display all values of a custom field from posts with a certain value of another custom field or from certain post types?

take a look at the reference docs for the WP_Query class: http://codex.wordpress.org/Class_Reference/WP_Query something like this: $args = array( //some key/value pairs…whatever ‘meta_query => array( array( ‘key’ => somekey, ‘value’ => somevalue, ‘compare’ => some comparison operator ), array( ‘key’ => some other key, ‘value’ => some other value, ‘compare’ => some comparison operator ) ) … Read more

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