Calling UDF (MS Access) from Excel VBA

Question

Hi,
I need to run a query on an MS Access database that has to perform a weekday calculation between two date columns,
and this query has two date parameters that it receives dynamically. I am using Excel VBA as the front end.
Select AgeRange, count(*) from
(Select IIF(networkdays(date1,date())<=2, "0-2 days","over 2 days")) as AgeRange
from table1
where date2 >= startdt
and date2 <=enddt
) d
group by AgeRange
The actual query is more complex, but this will help illustrate the issue. I build a string variable with
the query, and substitute Startdt and enddt variables with the actual values. I then create a new QueryDef object and get the results from OpenRecordSet.
Except, Networkdays is not a valid function in MS Access. So, this query fails.
I created a WorkDays UDF in MS Access, and used that instead - the query works fine in MS Access, but when
I try to pass it in the QueryDef object, it fails with 3085 error (function not available).
I'm not sure how to get around this, and could use some help.
In summary, I need to run a select query that will calculate weekdays or workdays between two columns (query
is dynamic - dates are variable) from VBA to MS Access, get the results back to VBA so that I can populate the results. Any suggestions are appreciated and welcome.
Thanks!
I tried using datediff with the "w" parameter, but that doesn't work as I had hoped - it gives the
number of weeks between the dates instead of weekdays
I realize that I could get all the data (without doing the group by) down into Excel and then, do the networkdays
formula calculation there, and summarize after that, but that is a very inefficient way - and defeats the purpose of having an access database in the first place. Getting tens of thousands of records is going to cause space issues in Excel too.

Answer 1

Hi Bob,
One solution is to create a table in the Access database storing all the dates in these years, add a column to determine if this date is a week day or not. And create another table to store the dates that are to be excluded from the working days.
In this way, you need to create a separate query to count the valid working days based on the two tables. So the most difficult thing is to create the table that contains all the dates, please check this VBA code snippet which helps you to insert all the
dates into the table.
Sub InsertDatesIntoTable()
Dim StartDate As Date
Dim EndDate As Date
Dim d As Date
Dim w As Integer
Dim IsWorkDay As Boolean
StartDate = #1/1/2015#
EndDate = #12/31/2015#
For d = StartDate To EndDate
Debug.Print d
w = Weekday(d, vbSunday) 'first day of the week is Sunday
If w = 1 Or w = 7 Then ' if the current day is Sunday or Satuday
IsWorkDay = False
Else
IsWorkDay = True
End If
'Here you can insert d and IsWorkDay into the table
Next d
End Sub
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