SQL IN parameter

[Guest_imported]

First, can you use the 'In' Parameter when the field is numberic. For instance: Where CustNo In (10,30,50)

to return the specified customer numbers? I can get it to work fine using a text based field (ie. Where MarkSeg In ('AC', 'CL' 'BR')

Now I know that I need the single quote for text and no quotes for numbers. However, I cannot get it to work.

Thanks