Form Level Validation Rull Doesn't Recoginize Null

[Terri]

I two dates on a form used to enter and update a table. The following form
level validation rule is on the Date Completed field

[Date Received] Or =[Date Received] Or =Null

If the user leaves the Date Received blank and enters the Date Completed the
validation rule is invoked. If the user then clears the date in the Date
Completed with the delete key, the rule is still invoked. How do I have to
format the rule so that the user can overcome entering the Date Completed
when they didn't intend to, or entered the Date Completed prior to entering
the Date Received?

Thank you in advance for your help.

Terri

 

[George Nicholson]

Null cannot be compared, just evaluated. "x = Null" will always be Null, no
matter what x is. Even "Null = Null" returns Null.

... =[Date Received] Or Is Null

--
HTH,
George

I two dates on a form used to enter and update a table. The following form
level validation rule is on the Date Completed field

[Date Received] Or =[Date Received] Or =Null

If the user leaves the Date Received blank and enters the Date Completed
the
validation rule is invoked. If the user then clears the date in the Date
Completed with the delete key, the rule is still invoked. How do I have
to
format the rule so that the user can overcome entering the Date Completed
when they didn't intend to, or entered the Date Completed prior to
entering
the Date Received?

Thank you in advance for your help.

Terri

 

[Terri]

Thank you for the information. Do you know of an alternate means of
accomplishing the goal of my validation rule?

Null cannot be compared, just evaluated. "x = Null" will always be Null, no
matter what x is. Even "Null = Null" returns Null.

... =[Date Received] Or Is Null

--
HTH,
George

I two dates on a form used to enter and update a table. The following form
level validation rule is on the Date Completed field

[Date Received] Or =[Date Received] Or =Null

If the user leaves the Date Received blank and enters the Date Completed
the
validation rule is invoked. If the user then clears the date in the Date
Completed with the delete key, the rule is still invoked. How do I have
to
format the rule so that the user can overcome entering the Date Completed
when they didn't intend to, or entered the Date Completed prior to
entering
the Date Received?

Thank you in advance for your help.

Terri

 

[Douglas J. Steele]

He gave you the alternative: use Is Null

--
Doug Steele, Microsoft Access MVP

(no e-mails, please!)

Thank you for the information. Do you know of an alternate means of
accomplishing the goal of my validation rule?

Null cannot be compared, just evaluated. "x = Null" will always be Null,
no
matter what x is. Even "Null = Null" returns Null.

... =[Date Received] Or Is Null

--
HTH,
George

I two dates on a form used to enter and update a table. The following
form
level validation rule is on the Date Completed field

[Date Received] Or =[Date Received] Or =Null

If the user leaves the Date Received blank and enters the Date
Completed
the
validation rule is invoked. If the user then clears the date in the
Date
Completed with the delete key, the rule is still invoked. How do I
have
to
format the rule so that the user can overcome entering the Date
Completed
when they didn't intend to, or entered the Date Completed prior to
entering
the Date Received?

Thank you in advance for your help.

Terri