Modifying JSON with YQL

In memory, YQL works with immutable values. When a query needs to change something inside a JSON value, think of it as constructing a new value from parts of the old one.

This sample query takes an input JSON named $fields, parses it, substitutes the a key with 0, deletes the d key, and adds the c key with value 3:

$fields = '{"a": 1, "b": 2, "d": 4}'j;
$pairs = DictItems(Yson::ConvertToInt64Dict($fields));
$result_pairs = ListExtend(ListNotNull(ListMap($pairs, ($item) -> {
    $item = if ($item.0 == "a", ("a", 0), $item);
    return if ($item.0 == "d", null, $item);
})), [("c", 3)]);
$result_dict = ToDict($result_pairs);
SELECT Yson::SerializeJson(Yson::From($result_dict));

Modifying JSON with YQL

See also