[SQL] How to find records which are present in multiple groups

Below is my scenario

Column A Column B
Group-A 1
Group-A 2
Group-A 1
Group-A 1
Group-B 3
Group-B 1
Group-B 5
Group-B 3

I need to Flag value 1 from Column-B as it is present in multiple group (Group-A and Group-B). Also value 5 present twice in Group-B is fine as it is not present in multiple Group.

I am expecting below Result:

Column A Column B
Group-A 1
Group-B 1

Any help either on sql or presto would work for me.

Continue reading...