delete from wp_posts where ID in (select wp_term_relationships.object_id from wp_term_relationships
left join wp_term_taxonomy on wp_term_relationships.term_taxonomy_id = wp_term_taxonomy.term_taxonomy_id
left join wp_terms on wp_term_taxonomy.term_id = wp_terms.term_id
where wp_terms.term_id = 3);

Delete all Wordpress posts that carry a specific term ID

wordpress

MySQL