Assuming that "myTable" is some type of Purchases table, wouldn't the second come out to be

  Where not exists(select 1 from my table)

?

>Hi everybody,
>
>I have the following criteria on my form:
>

>Quotes Generated for Manufacturer [         ]            Model         [              ]
>    Exclude Customers who have purchased
>    Exclude Customers who haven't purchased
> Model year from [  ] through [  ]

>
>I'm trying to translate this into where condition.
>
>Exclude customers who have purchased is clear enough:
>

>where not exists (select 1 from myTable where Make = [] and Model = [] and Model year between [] and [])
>

>But how should I translate the second possibility - Exclude Customers who haven't purchased?
>
>Thanks in advance.