In earlier version of BigQuery SQL, DISTINCT clause is not supported. To retrieve distinct values, we had to use GROUP BY or Windowing function to deduplicate. In 2020, BigQuery already support DISTINCT clause thus we can directly use it in SELECT statement.
SELECT DISTINCT
WITH SRC AS ( SELECT 'A' AS Col1, 1 AS Col2 UNION ALL SELECT 'A' AS Col1, 1 AS Col2 ) SELECT DISTINCT * FROM SRC;
Output (in JSON format):
[ { "Col1": "A", "Col2": "1" } ]