PHP gets the day before, one months before the time of the previous year

Get the day before:

$mytime = Date ("y-m-d h:i:s", Strtotime ("1 day"));

Get three days ago:

$mytime = Date ("y-m-d h:i:s", Strtotime ("3 day"));

Get the time of the first one months:

$mytime = Date ("y-m-d h:i:s", Strtotime ("1 month"));

Get the time of the first 3 months:

$mytime = Date ("y-m-d h:i:s", Strtotime ("3 month"));

Get the first one hours:

$mytime = Date ("y-m-d h:i:s", Strtotime ("1 hour"));

Get the time of the previous year:

$mytime = Date ("y-m-d h:i:s", Strtotime ("-1 Year"));

PHP gets the day before, one months before the time of the previous year