## Metadata * URL: [https://www.burnison.ca/notes/fun-mysql-fact-of-the-day-duplicate-weedout](https://www.burnison.ca/notes/fun-mysql-fact-of-the-day-duplicate-weedout) * Published Date: 2019-05-21 * Author: [[richard-burnison|Richard Burnison]] ## Highlights * MySQL will calculate a unique hash of the row IDs for the outer table and check for its presence in the temporary "weedout"