BigQuery - Time Chunking

Show timestamps as being in their corresponding chunk of time.

e.g.
In this case show the current timestamp as the current quarter hour time chunk.
So 2026-04-22 12:43:00 would show as 2026-04-22 12:30:00.

SELECT
  TIMESTAMP_ADD( TIMESTAMP_TRUNC(CURRENT_TIMESTAMP(), HOUR) , INTERVAL (CAST(EXTRACT(MINUTE FROM CURRENT_TIMESTAMP()) / 15 AS INT64) * 15)  MINUTE)