SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function arrayFirst (children 1)
     ExpressionList (children 2)
      Function lambda (children 1)
       ExpressionList (children 2)
        Function tuple (children 1)
         ExpressionList (children 1)
          Identifier x
        Function materialize (children 1)
         ExpressionList (children 1)
          Literal UInt64_1
      Function arrayMap (children 1)
       ExpressionList (children 2)
        Function lambda (children 1)
         ExpressionList (children 2)
          Function tuple (children 1)
           ExpressionList (children 1)
            Identifier x
          Function toString (children 1)
           ExpressionList (children 1)
            Identifier x
        Literal Array_[UInt64_1, UInt64_2, UInt64_3]
