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Peter Waters
13,327 PointsCannot get this join to work
I can't get this MySQL query to work. It's probably something really obvious, but if someone could point me in the right direction I'd really appreciate it!
The question was:
We will be writing ONLY the SQL query for this challenge. The library database contains a Media table with the columns media_id, title, img, format, year and category. It also contains a Genres table with the columns genre_id and genre. To join these tables, there is a Media_Genres table that contains the column media_id and genre_id
Add to the following SELECT statement to JOIN the Media table and the Genres table using the joining table Media_Genres.
The query
SELECT *
FROM Media
JOIN Media_Genres ON Media.media_id = Media_Genres.media_id
JOIN Genres ON Media_Genres.genre_id = Genres.genre_id
WHERE Media.media_id = 1;
5 Answers
anil rahman
7,786 PointsI don't see anything wrong with your syntax. I don't see why you have the where clause, don't see it being asked for in the question.
Peter Waters
13,327 PointsHi John,
I've just tried this challenge again and it's a bit confusing. Here's the full working query:
SELECT * FROM Media JOIN Media_Genres ON Media.media_id = Media_Genres.media_id
JOIN Genres ON Media_Genres.genre_id = Genres.genre_id
WHERE Media_Genres.media_id = 3;
Basically the value of media_id has to be 3, otherwise the query fails. If you run the query without the WHERE clause you'll see that the only results have an id of 3. If you use any other value you get the error Bummer! Nothing needs to be removed, you need to add a JOIN for the Genres ON the genre_id column in both the Media and Genres tables.
John Shockey
45,061 PointsI ended up figuring it out... this ended up working for me:
SELECT * FROM Media JOIN Media_Genres ON Media.media_id = Media_Genres.media_id JOIN Genres ON Genres.genre_id = Media_Genres.genre_id WHERE Media_Genres.media_id = Media.media_id
Peter Waters
13,327 PointsSorry, I left out the bit of the question that says:
NOTE: You will need to add the table to the WHERE clause so that the media_id column is not ambiguous.
I managed to solve it. The WHERE clause should have WHERE Media_Genres.media_id = 1 not WHERE Media.media_id = 1
Thanks for your reply!
John Shockey
45,061 PointsHey Peter,
How did you solve this? Here is my SQL statement:
SELECT * FROM Media JOIN Media_Genres on Media.media_id = Media_Genres.media_id JOIN Genres on Media_Genres.genre_id = Genres.genre_id WHERE Media_Genres.media_id = 1;
I am getting the error:
Bummer! Nothing needs to be removed, you need to add a JOIN for the Genres ON the genre_id column in both the Media and Genres tables.
Kazi Ahmed
11,367 PointsSELECT * FROM Media JOIN Media_Genres ON Media_Genres.media_id = Media.media_id JOIN Genres ON Genres.genre_id = Media_Genres.genre_id WHERE Media_Genres.media_id=3;
anil rahman
7,786 PointsMaybe this challenge is a two part challenge so when you are adding the where clause in, its erroring because that's the next step?