Syntax Error on a DLookup Criteria

[Adam Tippelt]

If DLookup("TS_ID", "TestsForScripts", "[Ref_ID]=" & Me.Ref_ID & " AND " & "[ExpectedResult]='" & Me.ExpectedResult & "'") = "" Then

Can anyone see anything wrong with this code? It keeps throwing up a Run Time Error 3075 message, saying there's a syntax error and I can't spot any.

Ref_ID is a numerical field, and ExpectedResult is a string based field.

Thanks.

[TheSmileyCoder]

You are trying to compare to an empty string. Usually Access does not store empty strings. If the field has not been used, it will be null, not a zero length string. You need to understand that there is a big difference between the two.

If you are worried that a DLookup could return null, there are a few things to do:
Enclose it in Nz, like so:

NZ(Dlookup_GOES_HERE,"")

If Dlookup returns a value the value gets returned from nz. If Dlookup returns Null, the empty string is returned.

A simpler way, which only works for strings, is to take advantage of the fact that: Null & ""=""

If Dlookup() & ""="" then 
  'Null was returned
End IF

[Adam Tippelt]

While I understand what you say, that isn't where the problem lies. The problem seems to exist in the dlookup itself, not the comparison.

The entire error message that comes up is:

Run-time error ‘3075’:

Syntax error (missing operator) in query expression ‘[Ref_ID]=410 AND [ExpectedResult]=’Invalid login details are blocked by the system, and the user is prompted that the details aren’t valid.”.

Don't know if that gives any clues.

From what I've deduced, the problem seems to be with ExpectedResult. This is only one field of many that are supposed to be in the criteria, and doing a dlookup with all fields except ExpectedResult runs without a problem. :S

[MikeTheBike]

Hi

Not withstanding TheSmileyCoder's excellent advice, I think your DLookUp() should be like this

DLookup("TS_ID", "TestsForScripts", "[Ref_ID]=" & Me.Ref_ID & " AND [ExpectedResult]='" & Me.ExpectedResult & "'")

assuming Ref_ID is numeric and ExpectedResult is text

??

MTB

[TheSmileyCoder]

I would guess that your problem comes from the fact that you have a single quote as a value in your expected results. Access so neatly handles the special charecters as long as they are in a field that we seldom remember (myself included) to handle them in vba.

Try this:

If DLookup("TS_ID", "TestsForScripts", "[Ref_ID]=" & Me.Ref_ID & " AND " & "[ExpectedResult]='" & Replace(Me.ExpectedResult,"'","''") & "'") = "" Then

[Adam Tippelt]

Once again SmileyCoder, you seem to have struck gold! The single quote in the value seems to be causing problems, and putting in your suggestion has solved the problem. I'll have to remember this one!

Thanks for the help.

[Adam Tippelt]

So much for me remembering this one - just got linked back to this thread while searching for an answer to the same problem!

[NeoPa]

LoL.

An important point to remember though Adam is What to Include in a Thread Asking for Help.