SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function JSONExtractKeysAndValues (children 1)
     ExpressionList (children 2)
      Literal \'{"a": "hello", "b": "world"}\'
      Literal \'LowCardinality(String)\'