SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function arrayFold (children 1)
     ExpressionList (children 3)
      Function lambda (children 1)
       ExpressionList (children 2)
        Function tuple (children 1)
         ExpressionList (children 2)
          Identifier acc
          Identifier x
        Identifier x
      Function materialize (children 1)
       ExpressionList (children 1)
        Function CAST (children 1)
         ExpressionList (children 2)
          Literal Array_[NULL]
          Literal \'Array(Nullable(UInt8))\'
      Function toUInt8 (children 1)
       ExpressionList (children 1)
        Function toNullable (children 1)
         ExpressionList (children 1)
          Literal UInt64_0
