Need help with Run time error 3075

[vaidehikumar]

I am getting run time error 3075 syntax error missing operator in query expression '[Job Number] = '

Here is my code:

Private Sub Job_Number_BeforeUpdate(Cancel As Integer)
If IsNull(DLookup("[Job Number]", "[Job]", "[Job Number]= " & Me.[Job Number] & " ")) Then
MsgBox "Job Number doesn't exist Enter a job number that already exist."
Cancel = True
End If
End Sub

 

[pbaldy]

As posted elsewhere:

Given the error, it appears that the form control is Null. Should it have an underscore? Also, why not use a combo box so the user can't enter a bad number?