Expression in select Query

[micko1]

Need help with query. I have a user form that allows users to select multiple controls. One of the controls is called [State]. In some cases there would be a need to select more than one [state]. I have placed another combo box on the form that allows the user to select the second state but not sure how to write the expression to get the correct results. If I type "NSW" Or "Vic" in the criteria filed it returns the results I am after. I have been using the expression below to return a single state or if Is Null all states.

[State]=[Forms]![frmQuotesINProgress]![cbostate] Or [Forms]![frmQuotesInProgress]![cboState] Is Null

Hope I have explained myself.
Thanks in advance for any assistance.

 

[John Big Booty]

Perhaps the attached sample will give you some pointers.

 

[micko1]

John Big Booty
Thanks very much for the assist. I managed to incorporate your sugestion and it work great. Thanks again
Mick