SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 2)
    Identifier a
    Identifier z
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Subquery (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 2)
          ExpressionList (children 2)
           Function sipHash64 (alias a) (children 1)
            ExpressionList (children 1)
             Identifier a
           Function plus (alias z) (children 1)
            ExpressionList (children 2)
             Identifier a
             Literal UInt64_1
          TablesInSelectQuery (children 1)
           TablesInSelectQueryElement (children 1)
            TableExpression (children 1)
             Subquery (children 1)
              SelectWithUnionQuery (children 1)
               ExpressionList (children 1)
                SelectQuery (children 3)
                 ExpressionList (children 1)
                  Identifier a
                 TablesInSelectQuery (children 1)
                  TablesInSelectQueryElement (children 1)
                   TableExpression (children 1)
                    TableIdentifier optimize_sorting
                 ExpressionList (children 1)
                  OrderByElement (children 1)
                   Function plus (children 1)
                    ExpressionList (children 2)
                     Identifier a
                     Literal UInt64_1
   ExpressionList (children 1)
    OrderByElement (children 1)
     Function plus (children 1)
      ExpressionList (children 2)
       Identifier a
       Literal UInt64_1
