Get the current Unix timestamp (seconds from 1970-01-01T00:00:00Z) in SQL.
- MySQL:
UNIX_TIMESTAMP()
- PostgreSQL:
CAST(EXTRACT(epoch FROM NOW()) AS INT)
- MS SQL:
DATEDIFF(s, '1970-01-01', GETUTCDATE())
- Oracle:
(CAST(SYS_EXTRACT_UTC(SYSTIMESTAMP) AS DATE) - DATE'1970-01-01') * 86400