Data Cleaning

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

String Cleanup

Real source data is messy. " Alice ", "alice", and "Alice" are three different strings to a database, but the same person to a human. String...

Dates arrive as strings more often than you'd like: "2024-03-15", "03/15/2024", "15-Mar-2024", "2024-03-15T14:22:11Z". To compare them, buck...

Before you dedupe, answer the harder question: what counts as a duplicate? Exact duplicates: every column the same. Key-duplicates: same pri...