SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 1)
    Function dictGetDescendants (children 1)
     ExpressionList (children 3)
      Literal \'01778_db.hierarchy_flat_dictionary\'
      Identifier number
      Literal UInt64_1
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier system.numbers
   Literal UInt64_6