$one_year = new DateInterval('P1Y');

$one_year_ago = new DateTime();

$one_year_ago->sub($one_year); //get the interval since 1 year ago

​

/*

Properties

​

y    Number of years.

m    Number of months.

d    Number of days.

h    Number of hours.

i    Number of minutes.

s    Number of seconds.

f    Number of microseconds, as a fraction of a second.

invert    Is 1 if the interval represents a negative time period and 0 otherwise. See DateInterval::format().

days    If the DateInterval object was created by DateTimeImmutable::diff() or DateTime::diff(), then this is the total number of full days between the start and end dates. Otherwise, days will be false.

from_string    If the DateInterval object was created by DateInterval::createFromDateString(), then this property's value will be true, and the date_string property will be populated. Otherwise, the value will be false, and the y to f, invert, and days properties will be populated.

date_string    The string used as argument to DateInterval::createFromDateString().

*/