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Databases

Chris Jones
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Chris Jones
Java Web Development Techdegree Graduate 23,933 Points
Posted by Chris Jones
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Chris Jones
Java Web Development Techdegree Graduate 23,933 Points

Counting Groups - SQL

I must be missing something really obvious. Below is the challenge. This is challenge #2 of 2 called Counting Groups in the Reporting with SQL course.

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.

I've tried both of the answers below: 

SELECT DISTINCT count(genre) AS total_genres FROM books
SELECT DISTINCT count(*) AS total_genres FROM books

I keep getting the same message: "Your query didn't perform the correct count."

Does anyone know what I'm doing wrong?

Thanks!

1 Answer

Umesh Ravji
Umesh Ravji
42,386 Points
Umesh Ravji
Umesh Ravji
42,386 Points

Hi Chris, you have the DISTINCT/COUNT statement/function in the wrong order. First you have to select all of the DISTINCT genre columns, and then COUNT how many of them there are.