How to make an aggregate formula COUNTIF with 2 conditions

How to make an aggregate formula COUNTIF with 2 conditions

Hi, I'm trying unsuccessfully to create an aggregate formula that counts items if 2 conditions are matched. I thought this would work:

countif("Sales Data"."Adhesive"='Yes',"Sales Data"."SalesAgent"='JH',NULL)

But it doesn't, the first part works, but the second part doesn't. Please can anyone help me with knowing how to do this successfully?

Also, is there a way to define in the formula which column it counts if these conditions are met?

Thanks

Jon