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 ...

Do you want to find out how to avoid duplicates in the results of a SQL SELECT query? This article will show you how.

Now we need to change all duplicate values to null. In other words, after grouping by the first two fields (or one of them), only the first record in the group remains unchanged, and the first two ...

-- Let's check for duplicate records. We'll use all the columns to check for any duplicate records.