Data type mismatch error....

[StephenD]

Hi everyone,

I've got what I thought would be a simple query but I can't get it to work.

I've got two fields: Membership ID and Number of months. I'm using a group by to count the number of membership Id's. This works fine until I add a third column to the query which is 'Age group'. Now the query doesn't work it comes up with the message
'Data type mismatch in criteria expression'

Has anyone got any ideas on where I'm going wrong?

Thanks!!