subtract intervals from dates
although in postgresql you can freely add/subtract dates/timestamps and intervals,
SELECT '2001-01-01'::timestamp + '1 year'::interval;
in mysql land you need to do use date_sub
and date_add
date_sub('2019-06-30' , interval 90 days)
Subtract dates
Also in postgresql you can just subtract dates,
'2021-01-01'::date - '2021-05-01'::date
And in mysql to do this you can do
DATEDIFF('2021-01-01', '2021-05-01')