Change the year of all posts in a particular category to 2012

query.sql

UPDATE wp_posts AS p
  JOIN wp_term_relationships AS tr ON tr.object_id = p.id
  JOIN wp_term_taxonomy AS tt ON tt.term_taxonomy_id = tr.term_taxonomy_id
  JOIN wp_terms AS t ON tt.term_id = t.term_id
  SET p.post_date = REPLACE(p.post_date, YEAR(p.post_date), 2012)
  WHERE t.slug = 'my-category-slug' AND tt.taxonomy = 'category';