LOWER()

Concepts: sqlLowerUpper

Basic Normalization All email addresses are now lowercase. This ensures consistency and makes comparisons reliable. Without normalization, 'Alice@Email.com' and 'alice@email.com' would be treated as different values. Case-Insensitive Compare By converting both sides of a comparison to lowercase, you can match strings regardless of case: Data Handling Preserving Original Data Non-Letter Characters Best Practices Case normalization is one of the most common data cleaning steps. Applying it consistently prevents subtle bugs that are hard to debug. When to Use LOWER() Always normalize case when uniqueness or comparison depends on text values. Many production bugs stem from failing to handle case inconsistencies.