Real-World Data Cleaning

Learn SQL real-world data cleaning with practical examples and guided drills on dbSyntax.

Tutorials teach SQL on spotless toy tables. Real tables are not spotless. The single most common complaint from people moving from tutorials...

Meet the Messy Data

Real data arrives dirty. Names are typed five different ways, "no email" hides behind blanks and the word n/a, dates come in whatever format...

Five cleaning drills on the messy tables, ordered easy to hard. Each isolates one real-world cleaning skill. The default editor shows a work...

Five data-cleaning drills, ordered easy to hard. The data is deliberately dirty: dates live in three different string formats, amounts carry...

Business brief. You have been handed a dirty export from two systems - messy_customers and messy_orders - and asked to report numbers leader...