How to Check for Duplicates Before Inserting Into SQL. When you insert new records into an SQL database, you may run into issues where you accidentally overwrite records that are already present ...

Duplicate and Ignore on MySQL Inserts. MySQL table primary keys and unique indexes prevent multiple rows with the same index from being added to the table. If you try to insert a duplicate row ...

Prevent duplicates before they happen by combining a simple function with data validation. Excel has built-in tools to expose and even delete duplicates, but they work on existing data after the fact.