Retrieve post tags from from main wp_query

Question

I'm running a custom WP_Query and find the following SQL running as part of it.

SELECT t.*, tt.*, tr.object_id FROM wp_terms AS t INNER JOIN wp_term_taxonomy AS tt ON tt.term_id = t.term_id INNER JOIN wp_term_relationships AS tr ON tr.term_taxonomy_id = tt.term_taxonomy_id WHERE tt.taxonomy IN ('category', 'post_tag') AND tr.object_id IN (381, 383, 389, 395) ORDER BY t.name ASC

Now within the loop I'm using wp_get_object_terms( $post->ID, 'post_tag' ); to retrieve post tags. This results in additional SQL queries for each post to retrieve post tags. Something I believe shouldn't be necessary when the post tags were fetched when the WP_Query initial ran.

WordPress is smart enough not to do this with post meta, as any number of calls to get_post_meta within the loop never results in additional SQL queries.

How can I retrieve the post tags and possibly the categories from the original WP_Query and avoid extra SQL queries.?

Answer 1

Resolved this by using get_the_tags($post->id); instead of wp_get_object_terms( $post->ID, 'post_tag' );.

get_the_tags($post->id); hooks onto the WP_Query within the loop and retrieves the tags without the need of additional SQL queries.