SQL String Functions

What & Why

Numbers and dates tend to arrive already well-formed. Text almost never does — names typed in all caps, emails with extra spaces, phone numbers formatted five different ways. This series covers the toolkit for combining text (CONCAT, ||), cleaning it (TRIM, UPPER/LOWER/INITCAP), measuring and slicing it (LENGTH, SUBSTRING, LEFT/RIGHT), finding and replacing pieces (POSITION, REPLACE, SPLIT_PART), and aggregating it across rows (STRING_AGG).

See How It Works

SELECT
  LOWER(TRIM(source)) AS normalized_source,
  COUNT(*) AS leads
FROM marketing.leads
GROUP BY 1
ORDER BY leads DESC, normalized_source ASC;