Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

Databases Reporting with SQL Aggregate and Numeric Functions Counting Groups

Posted by Kawaljeet Singh
Kawaljeet Singh
3,820 Points

GROUP BY

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.

My Answer- select COLUMN(DISTINCT genre) AS "total_genre" from books GROUP BY genre PLease highligh my mistake and explain the answer. Thank you

1 Answer

Steven Parker
Steven Parker
231,275 Points
Steven Parker
Steven Parker
231,275 Points

The challenge error message contained a hint: "Bummer: You're missing the COUNT() function."

That's one of three issues:

  • you have "COLUMN" instead of "COUNT"
  • you have "total_genre" (singular) but the instructions asked for "total_genres"
  • you don't need GROUP BY for this
Kawaljeet Singh
Kawaljeet Singh
3,820 Points

Hi I still tried but its not proper answer. select COUNT(DISTINCT genre) AS total_genres from books GROUP BY genre;

Steven Parker
Steven Parker
231,275 Points
Steven Parker
Steven Parker
231,275 Points

Kawaljeet Singh — Ooops, I forgot there was a third issue. I updated my answer.
Did you get it now?