Use the dot notation to query nested elements and the array notation for selecting items in an array. The example below uses a JSON nested string and uses Cloud9QL to parse it.
select nestedObj.a, nestedArr[0], nestedObj.secondLevel.x as Second Level Object,nestedObj.secondLevel.y[1] as Second Level Array, sent
where nestedArr[0]=150
To unwind/expand an array, use the expand syntax.
Example:
select customer, nestedObj.secondLevel.y as Nested;
select expand(Nested);
Note that expand must be specified on its own, without any other elements within the select.