Re: unique index with several columns - Mailing list pgsql-sql

This should solve the task:

create unique index idx on t ((
        case
                when c1 is null and c2 is null then null
                when c1 is null and c2 is not null then '{c2}'
                when c1 is not null and c2 is null then '{c1}'
                else '{c1,c2}'
        end));