Query Question

For the subform it's easier to show by default all rows and apply a filter when the textfield(s) are filled.

Make the subform based on:
SELECT *
FROM cbsofeed_more
UNION
SELECT * FROM cbsofeed_less;

add a button and code in the OnClick:

Me!subBlank.Form.filter = "[Corp_ID_Control_Acct]='" & me.txtFindAccount & "'"
Me!subBlank.Form.filterOn =  True

To reset the filter you could add a button with:
Me!subBlank.Form.filteron = false

Clear ?

Nic;o)

Hmm, finally you could change your txtFindAccount into a combobox based on the union query (let's call it qryCorpUnion).
Make the combo's source:
select distinct Corp_ID_Control_Acct from qryCorpUnion

Now the user can only select existing codes and you're able to link the subform to this combo. Thus Access will synchronize the subform with the combo automatically.

Idea ?

Nic;o)

Thanks Nico.  Your first option worked perfectly.  Now to the second problem, getting the results to show up in the subform.

Nico, in response to your suggestions, the first one won't work because the result is a query that takes forever to complete.  Right now the time to completion is about 1-2 seconds, whereas if I do a UNION without attaching the criteria driectly to each table, i.e. Select * From cbsofeed_more WHERE acct_num = 123456 UNION Select * from cbsofeed_less WHERE acct_num = 123456.  In regards to the second option, for each month there are approximately 200,000 unique records, so I don't think the combobox option will work.

Thanks!

OK, as usual there are more roads possible to solve this.

When you have a monthly bulk import you could store the distinct Acct values in a table and use that for the combo solution.
In general the filter will work rather fast as the query it's based on will be prepared by Access.

Another option is to dynamically create the query in code. I often use two queries for this, one "basic" one and the real one.
The "basic" would look like:
SELECT *
FROM cbsofeed_more WHERE [Corp_ID_Control_Acct] = 999999999
UNION SELECT * FROM cbsofeed_less WHERE [Corp_ID_Control_Acct] = 999999999;

The second is filled with the edited "basic" one like:
dim qd1 as dao.querydef
dim qd2 as dao.querydef

set qd1 = currentdb.querydefs("qryCorpBasic")
set qd2 = currentdb.querydefs("qryCorpReal")

qd2.SQL = Replace(qd1.SQL,"999999999",me.txtFindAccount)

That's all. After execution qryCorpReal will have the entered Account and the subform based on the query will show the result.

Need more ?

Nic;o)

Nico, OK, you lost me.  I have been looking at your last suggestion throughout the day, and I don't understand what exactly you are doing while creating the dynamic code for the query.  Please understand I know enough VB to be dangerous, so I am not a pro, although would like to learn if you can explain the answer in more simplistic terms.

Thanks!