Identify Firewalllog Connections via VPNlog Connections

Hello everybody,

after getting some other issues running, i'm stucking again.

I have to tables: FIREWALLLOG and VPNLOG

FIREWALLLOG Format:      Date, Time, Timestamp, SourceIP, DestIP

VPNLOG Format:               Date, Time, Timestamp, InternalIP, DestIP, OriginalClientIP, Username

I want to identify firewalllog entries over the vpnlog entries.

In some cases, the OriginalClientIP = DestIP from Firwalllog. So i want to add the username to the firewalllog entries, if OriginalClientIP = DestIP from Firewalllog.

I tried a join of both tables, and it worked, but i then got the same Firewall entrie many times, because there are maybe 20 entries in vpn with the OriginalClientIP = DestIP condition.

So it has something to do with distinct values. is it possible, to filter out all distinct OriginalClientIP of a User and then join them with the firewalllog?

Regards,