use strict; use warnings; use DBI; use Time::Seconds; use Time::Piece::MySQL; my $dbh = DBI->connect( ... ); my $sth = $dbh->prepare('update events set date = ? where id = ?'); my $dates = $dbh->selectall_arrayref( 'select id,date from events', {Slice => {}} ); for (@$dates) { my $date = localtime->from_mysql_datetime( $_->{date} ); $date += ONE_DAY * 50; $sth->execute( $date->mysql_datetime, $_->{id} ); }