How to set the year part of a field using a query

Question

Evening,

I have created a query that is suppose to change ONLY the year part of a Date/Time field to 1900 when a person is 89 years or older. The query that follows compiles fine but when run it complains about a Type Conversion failure and removes the entire value from the records affected.

The query:

UPDATE tblTestForDOB
SET tblTestForDOB.[PT_BirthDate] = DateValue( (day([PT_BirthDate])/month([PT_BirthDate])/1900) )
WHERE Year(tblTestForDOB.[PT_BirthDate]) <= Year(Date())-"89";

According to the MS Help (F1 over the function):

The required date argument is normally a string expression representing a date from January 1, 100 through December 31, 9999. However, date can also be any expression that can represent a date, a time, or both a date and time, in that range.

Is that not what I'm doing? I also tried placing the " " & before the values inside the DateValue function and that did the same thing (to ensure that it was a string that was passed)

So how do I go about it? Should I use CDate to convert the value to a Date and then proceed that way? If so what is the correct syntax for this?

Thanks

P.S The field is of Short Date format. Also note that I don't want to take the long way around and use VBA for the whole thing as that would involve opening record sets and so on...

Answer 1

It appears you're trying to give DateValue a string, but that's not what's happening. There may be more going on that I don't understand, so I'll just show you an Immediate window session which may contain something you can build on.

PT_BirthDate = #1923-6-1#
? PT_BirthDate
6/1/1923 
? DateDiff("yyyy", PT_BirthDate, Date())
 90 

' this throws error #13: Type mismatch ...
? DateValue( (day([PT_BirthDate])/month([PT_BirthDate])/1900) )

' it will work when you give DateValue a string ...
? DateValue("1900-" & Month(PT_BirthDate) & "-" & Day(PT_BirthDate))
6/1/1900 
' or consider DateSerial instead ...
? DateSerial(1900, Month(PT_BirthDate), Day(PT_BirthDate))
6/1/1900