SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 1)
    Function dictGet (children 1)
     ExpressionList (children 3)
      Literal \'01681_database_for_flat_dictionary.flat_dictionary_simple_key_hierarchy\'
      Literal \'parent_id\'
      Identifier number
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier system.numbers
   Literal UInt64_5