Which BigQuery queries cost me the most last month?

-- Top queries by on-demand cost, last 30 days.
-- Change 6.25 to your region's per-TiB rate if you are not in US/EU.
SELECT
  job_id,
  user_email,
  DATE(creation_time)                                   AS run_date,
  total_bytes_billed,
  ROUND(total_bytes_billed / POW(1024, 4), 3)           AS tib_billed,
  ROUND(total_bytes_billed / POW(1024, 4) * 6.25, 2)    AS est_on_demand_usd,
  TIMESTAMP_DIFF(end_time, start_time, SECOND)          AS runtime_seconds,
  cache_hit,
  SUBSTR(REGEXP_REPLACE(query, r'\s+', ' '), 0, 300)    AS query_preview
FROM `region-us`.INFORMATION_SCHEMA.JOBS_BY_PROJECT
WHERE creation_time >= TIMESTAMP_SUB(CURRENT_TIMESTAMP(), INTERVAL 30 DAY)
  AND job_type = 'QUERY'
  AND state = 'DONE'
  AND error_result IS NULL
ORDER BY total_bytes_billed DESC
LIMIT 50;