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Development Tools Database Foundations SQL Calculating, Aggregating and Other Functions Grouping, Joining and Cleaning Up

Posted by Ian Corritore
Ian Corritore
4,740 Points

Group, Joining, and Filter in SQL.

I am stumped on this segment: Like before, select the average "score" as "average", setting to 0 if null, by grouping the "movie_id" from the "reviews" table. Also, do an outer join on the "movies" table with its "id" column and display the movie "title" before the "average". Finally, filter out any "average" score over 2. Here is my code:

SELECT title, IFNULL(AVG(score).0) AS average FROM movies LEFT OUTER JOIN reviews ON movies.id = reviews.movie_id GROUP BY movie_id HAVING average < 2;

Where am I going wrong?

Dave McFarland
Dave McFarland
Treehouse Teacher
Dave McFarland
Dave McFarland
Treehouse Teacher

Hi Ian,

Your SQL code wasn't showing up correctly. I fixed it in your post. For the future, to put code in a forum post:

  1. hit return to create a new line and type three back tick characters ```

  2. hit return to create another new line and paste your HTML

  3. hit return and add three more back tick characters: ``` The back tick character isn't the same as the single quote -- ' -- mark; the back tick is located on the same key as the ~ on most keyboards.

Also to add correct color highlighting add the name of the language after the back ticks like this: ```CSS. Here's what CSS should look like in a forum post:

#gallery li {
  float: left;
  width: 45%;
}

1 Answer

bothxp
bothxp
16,510 Points
bothxp
bothxp
16,510 Points

Hi Ian,

My answer was:

SELECT title, ifnull(avg(score),0) as average 
FROM movies left outer join reviews 
ON movies.id = reviews.movie_id 
GROUP BY movie_id 
HAVING average <= 2;

It looks like you have a . instead of a , in the IFNULL