UPDATE classes
SET `date` = DATE_ADD(`date`, INTERVAL 2 DAY)
WHERE id = 161
SELECT GETDATE() 'Today',
DATEADD(day,-2,GETDATE()) 'Today - 2 Days'
SELECT GETDATE() 'Today',
DATEADD(dd,-2,GETDATE()) 'Today - 2 Days'
SELECT GETDATE() 'Today',
DATEADD(d,-2,GETDATE()) 'Today - 2 Days'
UPDATE classes
SET `date` = DATE_ADD(`date` , INTERVAL 2 DAY)
WHERE `id` = 161;