How MySQL Optimizes DISTINCT? DISTINCT is converted to a GROUP BY on all columns and it will be combined with ORDER BY clause. Share :Click to print (Opens in new window)Click to share on Reddit (Opens in new window)Click to share on Tumblr (Opens in new window)Click to share on Pocket (Opens in new window)Click to share on LinkedIn (Opens in new window)Click to share on Twitter (Opens in new window)Click to share on Pinterest (Opens in new window)Click to share on Facebook (Opens in new window)