Preserve index usability in predicates.
Section: Index Strategy
Avoid wrapping indexed columns in functions
sql
sql
-- Less index-friendly
SELECT *
FROM users
WHERE LOWER(email) = 'a@example.com';
-- Prefer normalized storage or computed/indexed support where available
SELECT *
FROM users
WHERE email = 'a@example.com';Explanation
Applying functions to indexed columns can prevent index usage in many engines.
Learn the surrounding workflow
Compare similar commands or jump into common fixes when this command is part of a bigger troubleshooting path.
Related commands
Same sheet · prioritizing Index Strategy
Index a common lookup column
Speed up frequent equality or range predicates.
Use a covering index pattern
Create an index that supports filtering and ordering efficiently.
Use keyset pagination
Paginate by a stable cursor instead of a large OFFSET.
Explain with runtime stats
Run a query and collect timing or actual row information where supported.