Good morning everyone, I know that there are similar topics, but in no way did I find a solution to this question, which although it seems simple is giving me problems.
Summing up. I have two tables. In a table has C_ID (referring to the courses that a university has). In the other table there is the Anolectiv (referring to the period in question 2016/2017, 2017/2018 ... etc) what I wanted to count the number of new courses. That is to say only in the courses that are only associated with the last period. I have experimented with several formulas of set analysis. But I can never get only the new courses.