I have a query that selects workorders from a table then trys to
calculate the total hours down by using the function:
DateDiff([h],[DAYDOWN]+[TIMEDOWN],[DAYUP]+[TIMEUP],1,1) AS THD.

Instead of doing the calculation it asks me for "h" which I understand
to be the interval and the proper symbol for hour. What am I doing
wrong?

«Expr» DateDiff («interval», «date1», «date2»,
«firstweekday», «firstweek»)

SQL text:

SELECT WORKORD.DAYDOWN, WORKORD.DAYUP, WORKORD.TIMEDOWN,
WORKORD.TIMEUP, WORKORD.MACHID, WORKORD.EMPLOYEE, WORKORD.ACTION,
WORKORD.REQUEST, WORKORD.COMMENT1, WORKORD.COMMENT2, WORKORD.WONO,
DateDiff([h],[DAYDOWN]+[TIMEDOWN],[DAYUP]+[TIMEUP],1,1) AS THD,
WORKORD.SUBSYS
FROM WORKORD;

Sample Result Data space separated:
DAYDOWN    DAYUP    TIMEDOWN    TIMEUP    MACHID    EMPLOYEE    ACTION    REQUEST    COMMENT1    COMMENT2    WONO    THD    SUBSYS
11/3/1998    11/3/1998    8:00    8:20    APT-006    KPM    PM    PM    none    none    34743    0    CHD
11/8/1998    11/8/1998    13:00    13:15    APT-014    RC    PM    PM    none    none    34745    0    FOC
11/4/1998    11/4/1998    17:15    18:40    ATQ-008    EG    PM    PM    none    none    34746    1    CHD
11/3/1998    11/3/1998    11:45    13:15    ATQ-028    WG    PM    PM    none    none    34748    2    CHD