unique post tags ni wordpress
$post_ids = get_posts(
array(
'posts_per_page' => -1,
'category_name' => 'testing',
'fields' => 'ids', // Just get the ID's, save a hella lotta memory
)
);
// Get and cache all post tags in one swoop
update_object_term_cache( $post_ids, 'post' );
// Build a unique index of tags for these posts
$tags = array();
foreach ( $post_ids as $post_id ) {
if ( $post_tags = get_object_term_cache( $post_id, 'post_tag' ) ) {
foreach ( $post_tags as $tag )
$tags[ $tag->term_id ] = $tag;
}
}
// Show em!
foreach ( $tags as $tag ) {
echo '<a href="' . get_term_link( $tag ) . '">' . $tag->name . '</a> ';
}