SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function if (children 1)
     ExpressionList (children 3)
      Function greater (children 1)
       ExpressionList (children 2)
        Subquery (children 1)
         SelectWithUnionQuery (children 1)
          ExpressionList (children 1)
           SelectQuery (children 2)
            ExpressionList (children 1)
             Function count (children 1)
              ExpressionList (children 1)
               Asterisk
            TablesInSelectQuery (children 1)
             TablesInSelectQueryElement (children 1)
              TableExpression (children 1)
               TableIdentifier system.time_zones
        Literal UInt64_500
      Literal \'ok\'
      Literal \'fail\'