When adding unique indexs to tables to prevent data duplication you discover there are already duplicates in the table you wish to fix/improve. Here’s a quick way to list records with duplicates. select count( id ) as cnt, id from table group by id having cnt > 1 You still have to go through and [...]

Here’s an decent article with various methods of finding duplicate data in databases with SQL. http://www.delphifaq.com/faq/delphi/database/f20.shtml Removing duplicate data can be a troublesome task as well. One of the fastest ways to do so involves creating a new table with a unique index to the column you wish to purge of duplicate data. Then you [...]