how to use a DateDiff & Calculation With Update Satatement ?

[loyal]

I am trying to subtract 2 dates in period Column

 

it works fine with Select Statement but

 

it will be meaning full if it works with Update Statement

 

also I wann subtract TotalDays from Period

 

can someone figure out what is my mistake in this script ?

 

 

UPDATE Vacation SET DateOfBack = ?, DateOfLeave = ?, 

LeaveKind = ?, MilitryNumber = ?, Period = ?, TotalDays = ? 

WHERE (VacationID = ?) AND (DateOfBack = ? OR ? IS NULL AND 

DateOfBack IS NULL) AND (DateOfLeave = ? OR ? IS NULL AND 

DateOfLeave IS NULL) AND (LeaveKind = ? OR ? IS NULL AND 

LeaveKind IS NULL) AND (MilitryNumber = ? OR ? IS NULL AND 

MilitryNumber IS NULL) AND (Period = DATEDIFF('d', DateOfLeave, 

DateOfBack) OR ? IS NULL AND Period IS NULL) AND (TotalDays = 

TotalDays - Period OR ? IS NULL AND TotalDays IS NULL)

Edited November 2, 2003 by Robby

[bungpeng]

"?" should be your variable right? then can you use "? is NULL..."?

[loyal]

I am sorry I coudn't get it

 

can you please post a code

[PlausiblyDamp]

What are you using as the database?

[loyal]

Hi I am using Access Database