Hi,

I'm wondering if anyone can help me with this type of data structure (see below):
IncidentId PersonId Cmpd
1 11 methanol
1 11 benzene
1 11 ethanol
1 11 toluene
1 11 diethyl ether
2 12 methanol
2 12 benzene
2 12 toluene
2 12 diethyl ether
So I want to be able to select a compound from this list and match them to the other one.

For example, I want to see how many cases involve both methanol and toluene, for example.

How would I go about checking for both or multiple compounds in such a scenario?

Thanks in advance