SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Identifier _shard_num
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Function cluster (children 1)
       ExpressionList (children 2)
        Identifier {default_cluster_macro}
        Identifier system.one