Duplicate records can quietly undermine the accuracy of any database, leading to flawed reports, skewed analytics, and operational inefficiencies. Whether you are managing a small customer list or a large enterprise data warehouse, knowing how to eliminate duplicate records in SQL is an essential skill for developers, data analysts, and database administrators. This guide walks you through the causes of redundancy, the most effective deletion techniques, and practical steps to keep your tables clean without risking data loss.
Understanding Duplicate Records in SQL
A duplicate record occurs when two or more rows in a table contain identical values across one or more columns. There are two main types of duplicates you should recognize. Exact duplicates are rows where every column matches, while business-key duplicates happen when rows share the same identifying information—such as an email address or product SKU
