SUBTOTAL from TOTALS?

I have a table:
ID--DATE--RegHours--Overtime--PTO
For RegHours, Overtime, PTO columns I have TOTALS.
How I can do just one SUBTOTAL for all TOTALS at the bottom of the list page?
I tried to use snipped on list page, but its not working. I understand that snippets cannot read data. I cannot use Session variables in this scenario.
sql = "select SUM(ISNULL(RegHours,0) + ISNULL(Overtime,0) + ISNULL(PTO,0)) from Timesheet WHERE id='" & data("id") & "'"

set rstmp=CustomQuery(sql)

Response.Write rstmp(0)

rstmp.close

set rstmp=nothing
Thank you!