I have a non-dev colleague that created a report in our pseudo-self service viz tool. Shortly after creating and forwarding said report, he submits a ticket stating "the data, in the db is wrong. Every time I run my report, the sum (of a numeric column) is five time more than (and here is the funny part) when I run the SQL in developer!" My response, after reading this ticket: "it is the same data, from the same db, and the same tables! CHECK YOUR JOINS!!!!" His response: " found the issue. My bad! The report used outer joins vs' inner joins." Then he resolved the ticket!