New Transact SQL Video Tutorial: Design Pattern for Finding Duplicate Data - A Simple Way to Spot Non-Unique Rows (Single Column Test)

Design Pattern for Finding Duplicate Data - A Simple Way to Spot Non-Unique Rows (Single Column Test) - view details

Let's say that you have a Primary Key on "SubscriberId" but you want to locate rows that live in the same Country - how would you do it? This query talks about spotting duplicates in a single column (like "Country" in this case). Primary Keys prevent duplicate data in the table but they don't necessarily prevent duplicates across non-key columns. This video is all about spotting single-column duplicates and it uses subqueries and the EXISTS operator to help you locate the dupes.

• Category: Design Patterns for Transact-SQL
• Skill Level: 300 (Intermediate)
• Length: 14:16 (10.8MB)
• Applies to Versions: SQL Server - All Versions
• Full Details

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