You can use a Union Query to do exactly that. I don't know what your SQL
looks like, but here is an example from one of my apps where the user can
select a specific record or All records. Of course, in all my event code I
have to check for that value being the current value of the combo:
SELECT DISTINCT Client.ClientID, Client.ClientName FROM (Client LEFT JOIN
Property ON Client.ClientID = Property.PropertyClientID) LEFT JOIN Contract
ON Property.PropertyID = Contract.ContractPropID WHERE
(((Contract.ContractType)="D")) AND Contract.ContractStatus LIKE
IIf(Forms!frmSubMtrInstMgr!cboStatus = "
","*",Forms!frmSubMtrInstMgr!cboStatus) ORDER BY Client.ClientName UNION
SELECT " " As Client, "[All Clients]" As ClientName FROM Client;