Since AWS Redshift don’t have function like FROM_UNIX(), it’s much more weird to get formatted time from a UNIX timestamp (called ‘epoch’ in Reshift):

SELECT timestamp 'epoch' + my_timestamp_column * interval '1 second' AS my_column_alias
FROM my_table

Ref: https://stackoverflow.com/questions/39815425/how-to-convert-epoch-to-datetime-redshift

If we want to see the statistics result group by hours:

SELECT
  COUNT(1),
  DATE_TRUNC('hour', timestamp 'epoch' + my.timestamp * interval '1 second') AS hour
FROM my_table AS my
WHERE my_table.my_timestamp_column > extract('epoch' from '2019-10-23'::TIMESTAMP)
GROUP BY hour
ORDER BY hour;