Unfortunately the table does not have a primary key. Each userID can have multiple entries.
A date in dtExam1 mens they attended Exam1 and same for Exam2. (eg) userID 123 has attended both exams on different dates. Thus it has 2 entries.
Now, I need all the users who have attended ONLY Exam1 and not attended Exam2. I thus need records like userID 567 but I also need to make sure that there is NO other record for userID 567 with dtExam2.
Besides backup, any IT division should have a disaster recovery plan. You will find a few tips below relating to the development of such a plan and to what issues one should pay special attention in the course of backup planning.
Why is this different from all of the other step by step guides? Because I make a living as a DBA and not as a writer and I lived through this experience.
Defining the name:
When I talk to people they say different names on this subject stuff l…