The IN operator in EdgeQL tests whether a given
element is present in a set. This operator has
features of a function that works on elements and of a
function that works on sets. More strictly the result of
A IN B is a set of boolean values indicating for each
element of A whether or not it is in B:
To check whether one set is a subset of another you can
combine the IN operator with the all built-in
function, effectively computing whether all elements of
the set A are in B:
