SQL Cleaning Data with String Functions

What & Why

Real category fields can differ only because of casing or extra whitespace. Queryflo keeps the original marketing.leads.source beside a normalized value so every cleanup decision remains auditable.

The worked pipeline applies TRIM, collapses repeated whitespace with REGEXP_REPLACE, and then applies LOWER. It standardizes presentation without overwriting the stored source value.

See How It Works

SELECT
  id AS lead_id,
  source AS raw_source,
  LOWER(REGEXP_REPLACE(TRIM(source), '\s+', ' ', 'g')) AS normalized_source
FROM marketing.leads
WHERE source IS NOT NULL
ORDER BY lead_id
LIMIT 20;