SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function dictGet (children 1)
     ExpressionList (children 3)
      Literal \'test_dictionary_non_nullable\'
      Literal \'value\'
      Function arrayJoin (children 1)
       ExpressionList (children 1)
        Function array (children 1)
         ExpressionList (children 3)
          Function toUInt64 (children 1)
           ExpressionList (children 1)
            Literal UInt64_0
          Literal NULL
          Literal UInt64_1
