Mysql automatic job or trigger ?

Short answer: you cannot make a trigger run at a time of day — triggers fire on table DML only. @tesuji was on the wrong track there; @chaosprime was right to point at an external scheduler. If the server is MySQL 5.1+ the simplest, self-contained choice is the MySQL Event Scheduler. If you run an older MySQL or prefer central scheduling, use cron / Task Scheduler to call a small script or a mysql CLI statement.

Example: a safe daily event that copies the most recent closeBalance into the next day while avoiding duplicates.

CREATE EVENT balance_snapshot_daily
ON SCHEDULE EVERY 1 DAY
STARTS '2008-07-25 22:00:00'
DO
  INSERT INTO Balance (todaysDate, openBalance, closeBalance)
  SELECT src.next_day, src.last_close, src.last_close
  FROM (
    SELECT DATE_ADD(CURDATE(), INTERVAL 1 DAY) AS next_day,
           closeBalance AS last_close
    FROM Balance
    ORDER BY todaysDate DESC
    LIMIT 1
  ) AS src
  WHERE NOT EXISTS (
    SELECT 1 FROM Balance b WHERE b.todaysDate = src.next_day
  );

Enable and check the scheduler before creating events:

SET GLOBAL event_scheduler = ON;
SHOW VARIABLES LIKE 'event_scheduler';
SHOW EVENTS FROM your_database;

Notes and practical tips: the account creating the event needs the EVENT privilege and the event runs with its DEFINER rights. Events use the server time zone; cron uses OS time — verify timezones match. If the server might be down at 22:00, a cron/script that checks for missing daily snapshots and backfills them is more robust. Test the SQL on a copy of the table first, and always include a NOT EXISTS or other idempotent guard so repeated runs don’t create duplicates.