Difference between joins in sql January 31, 2014Posted by javafoo in Uncategorized.
Have been on the other side of the fence lately, doing interviews. One of my peer developer on the team asked the potential interviewee, the difference between inner joins and outer joins. That had me thinking, since as a Java developer, if someone had asked me that outright, I wouldn’t have been able to give them a direct answer. But I would have ventured some explanation related to set theory about intersections and unions etc. And if I were actually writing a query I can get it right for the most part. So posting this really great visual explanation from codeproject. Diagram is from their site as well. Now what did the interviewee answer, well something like: I will try to recall, it’s been a while since I worked with Oracle database. I don’t think we will be hiring this person, not because they haven’t worked with Oracle database, but since they think this concept only applies to Oracle.