TIL - 250123

URL : https://datalemur.com/questions/uncategorized-calls-percentage

SELECT
  ROUND(
  100.0*
  (
    SELECT
      count(case_id)
    FROM callers
    WHERE call_category IS NULL
    OR call_category = 'n/a'
  ) / count(case_id)
  ,1)
FROM callers