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Cristian Luca
4,102 PointsWhat's wrong with my code? Thanks a lot!
Challenge Task 2 of 2 In the library database there's a books table. There are id, title, author, genre and first_published columns.
Write a query to count all the unique genres in the books table. Alias it as total_genres.
Cristian Luca
4,102 PointsSELECT DISTINCT genre, COUNT(*) AS total_genres FROM books;
What's wrong with my code? Thanks a lot!
3 Answers
Steven Parker
231,172 PointsThe instructions ask you to "count all the unique genres in the books table". So you only need one column in your result for the count (you won't need the genre). But you were on the right track about using "DISTINCT genre", it just needs to be what you're counting:
SELECT COUNT(DISTINCT genre) AS total_genres FROM books;
Guillermo Gallo
Full Stack JavaScript Techdegree Student 8,518 PointsYour code looks good so far, but I think instead of DISTINCT, you should try using a GROUP BY clause in your query. Keep in mind that the GROUP BY clause will go at the end of the query. So try something like this:
SELECT COUNT(*) AS total_genres FROM books GROUP BY genre;
Let me know if that works.
Guillermo Gallo
Full Stack JavaScript Techdegree Student 8,518 PointsYes, what Steven Parker said. What I suggested actually does not seem to work.
Steven Parker
231,172 PointsSteven Parker
231,172 PointsYou repeated the challenge, but forgot to show your code. Add it so we can give you an answer.