>>80
SQL-Server
ｓelect dates.date1 as date1, ｓum(ｃoalesce(table1.guests, 0)) as guests
ｆrom table1
ｒight join (
ｓelect startdate as date1 from table1
ｕnion
ｓelect enddate as date1 from table1
) dates on table1.startdate <= dates.date1 and dates.date1 < table1.enddate
ｇroup by dates.date1
ｏrder by dates.date1