SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Asterisk
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Function cluster (children 1)
       ExpressionList (children 3)
        Literal \'test_cluster_two_shards\'
        Identifier system
        Identifier one