/** * date_time_subtract * same as date_time_add except subtracting value instead of adding. * * @param \EE_Base_Class $obj * @param string $datetime_field_name name of the EE_Datetime_Filed datatype db column to be manipulated * @param string $period * @param int $value * @return \EE_Base_Class */ public static function date_time_subtract(EE_Base_Class $obj, $datetime_field_name, $period = 'years', $value = 1) { //get the raw UTC date $DateTime = $obj->get_DateTime_object($datetime_field_name); $DateTime = EEH_DTT_Helper::calc_date($DateTime, $period, $value, '-'); return EEH_DTT_Helper::_set_date_time_field($obj, $DateTime, $datetime_field_name); }