--this will update only one row that matches id = 1
update sessions
set start_date = '2020-04-20 10:12:15.653',
    end_date = '2020-04-22 15:40:30.123'
where id = 1;

--this will update multiple rows that match category = 1
update sessions
set end_date = null
where category = 1;

update sessions
set end_date = '2020-04-04 16:57:53.653';

update sessions
set start_date = '2020-04-02 14:05:15.400',
    end_date = '2020-04-04 16:57:53.653';