MS Access / SQL - Applying a time condition to multiple queries at once

I have 300+ queries which fetch information from my database. Right no开发者_运维百科w, there is no time condition specified in the queries, so if I wanted to filter all of them by a certain time period, i.e. Between #07/01/2009# And #08/01/2009#, I would have to manually go in each query and add this condition.

All of my queries are populating data into 4 main reports. What I am trying to do is apply a time filtering criteria like the one above to all of my queries at once, so that I can create a weekly report, as well as the Totals report (which just means there's no time condition).

Is there any easy way to add a single parameter before pulling my report that would filter all of my queries at once, and to pull the Totals report if it the parameter field were blank?

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You can use a reference to a form control within the WHERE clause of a query. So, for example, if I have an open form named frmDatePicker which includes a text box control named txtStartdate, I could use that control's value as a WHERE condition.

SELECT *
FROM MyTable
WHERE my_date_field >= Forms!frmDatePicker!txtStartDate;

That approach can work, but I have no idea whether it's an appropriate fit for your situation. You would have to modify all of your queries which include that date condition. That could be a one-time-only change. But if you ever change the form and/or control name, you'd have the revise the queries again. (So try not to do that!)

Edit: If you want to allow the user to leave txtStartDate blank, so as not to filter on that date at all, try a WHERE clause like this:

WHERE
    my_date_field >= Forms!frmDatePicker!txtStartDate
    Or Forms!frmDatePicker!txtStartDate Is Null;