Lets say i have 2 tables which are videogames and developers.
Under the videogames table, we have the following attributes:
- videogameid(PK)
- title
- dateOfRelease
Under the developer table, we have attributes:
- developerid(PK)
- name
- position
I tried finding the total number of videogames that had more than 5 developers. Here is my attempt to resolve the issue.
SELECT COUNT(videogameid) FROM videogames, developers WHERE videogameid = developerid GROUP BY developerid HAVING COUNT(developerid) > 5;
While I did not get any error issues but no results popped up.The result was null and not even zero.Hence i might have done something wrong.
EDIT: Yes there is one more table that actually relates to them it was videogames2developers which has the following attributes:
-videogameid -developerid -genre
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Answer
The bridge table videogames2developers suffices for this task. First get all video games with more than five developers, then count how many these are.
select count(*) from ( select videogameid from videogames2developers group by videogameid having count(*) > 5 ) games_with_more_than_five_devs;
This assumes that there is one entry per game and developer in the table. If this is not the case, then replace having count(*) > 5
by having count(distinct developerid) > 5
.