Translating OQL

select distinct hotel.price

from hotel in ( select h

from c in Cities,

h in c.hotels

where c.name = “Arlington” )

where exists r in hotel.rooms: r.bed_num = 3;

?{ hotel.price | hotel ? ?{ h | c ? Cities, h ? c.hotels,

c.name = “Arlington” },

?{ r.bed_num = 3 | r ? hotel.rooms } }

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Almost all OQL features can be mapped directly to monoid comprehensions. The above OQL query finds all hotels in Arlington with at least one room with three beds.