Check50 passes incorrect solution for 'movies' using distinct name instead of id

[chriscarrollsmith]

Instructions for 'movies' include this line:

"Executing 9.sql results in a table with 1 column and 19,325 rows."

My initial, incorrect solution passed check50 even though it returned only 19,261 rows. (My error was in using DISTINCT on 'name' rather than 'id', which evidently excludes some distinct people who have identical names.)

Here's the incorrect solution that passed the check:

SELECT DISTINCT(name)) FROM people JOIN stars ON people.id = stars.person_id WHERE movie_id IN (SELECT id FROM movies WHERE year = 2004) ORDER BY birth;

[bxngyn]

Thanks for your comment!

You do make a good point. The online specification says If a person appeared in more than one movie in 2004, they should only appear in your results once. However, this contradicts the instruction that Executing 9.sql results in a table with 1 column and 19,325 rows. This row count would only be 19,325 if we did make people appear more than once. The reason check50 still passes is that it uses a much smaller database to run the queries, which bypasses this discrepancy of duplicate people. We will make an update to the instructions and the database to account for this.

[rongxin-liu]

We should re-visit #266

Relevant PRs:
#285
#303
#350