Adding Hours Worked in 2 Rows

I have a table that has clock in time in one row and clock out time in another row. I need to be able to sum the hours worked in a day.

TIMESTAMP ETEMP# ETIORO PMNAME
1/2/09 8:56 AM 213 I John Deere
1/2/09 1:15 PM 213 O John Deere
1/2/09 1:43 PM 213 I John Deere
1/2/09 6:03 PM 213 O John Deere

I created two queries in access, one with clock in data and one with cloc out data and added the field DateVal for the day. I then created a query with the following SQL language.

SELECT ClockIn.DateVal, ClockIn.[ETEMP#], ClockIn.PMNAME, ClockIn.ETIORO, ClockOut.ETIORO, ClockIn.TIMESTAMP, ClockOut.TIMESTAMP, DateDiff("n",[clockin].[timestamp],[clockout].[timestamp])/60 AS [Hours]

FROM ClockIn INNER JOIN ClockOut ON (ClockIn.[ETEMP#]=ClockOut.[ETEMP#]) AND (ClockIn.DateVal=ClockOut.DateVal)

WHERE (((ClockIn.DateVal)=#1/2/2009#) And ((ClockIn.PMNAME)="John Deere"));

This is the result I get:

DateVal ETEMP# PMNAME ClockIn.ETIORO ClockOut.ETIORO ClockIn.TIMESTAMP ClockOut.TIMESTAMP Hours
1/2/09 213 John Deere I O 1/2/09 1:43 PM 1/2/09 1:15 PM -0.466666667
1/2/09 213 John Deere I O 1/2/09 8:56 AM 1/2/09 1:15 PM 4.316666667
1/2/09 213 John Deere I O 1/2/09 1:43 PM 1/2/09 6:03 PM 4.333333333
1/2/09 213 John Deere I O 1/2/09 8:56 AM 1/2/09 6:03 PM 9.116666667

How do I eliminate the duplication and get true hours worked for the day. I think it can be done with a subquery, but that is out of my league. Any help is greatly appreciated.

trater04, I can't test it but something like this might work:

Code:

---

SELECT col-list
FROM (SELECT col-list
      FROM table
      WHERE ETIORO = 'I'
    ) AS STR_DATA
  , (SELECT col-list
      FROM table
      WHERE ETIORO = 'O'
    ) AS END_DATA
WHERE STR_DATA.ETEMP# = END_DATA.ETEMP#
  AND END_DATA.TIMESTAMP =
        (
          SELECT MIN(TIMESTAMP)
          FROM table END_DATA2
          WHERE END_DATA2.TIMESTAMP > STR_DATA.TIMESTAMP
            AND END_DATA2.ETIORO = 'O'
        )

---

You can add your own COL-LIST columns and the date arithmetic but this should pair the starting IN time with the correct OUT time.