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Development Tools Database Foundations Joining Relational Data Between Tables in SQL Joining Tables and Aliasing

Taylor Rogers
Taylor Rogers
806 Points
Posted by Taylor Rogers
Taylor Rogers
806 Points

I am having trouble on the second task. I'm not sure I'm understanding this correctly.

I am having trouble selecting all of the movies, regardless of whether the 'genre_id' exists or not. Below is the join that I wrote and it doesn't seem to be working. I've tried changing it up a bit with no luck. Any help would be appreciated!

SELECT movies.title, genres.name FROM movie LEFT OUTER JOIN genres ON movies.genre_id=genres.id WHERE movies.genre_id IS NOT NULL;

2 Answers

Lukas Smith
Lukas Smith
4,026 Points
Lukas Smith
Lukas Smith
4,026 Points

U doing SELECT movies.title, genres.name FROM movie ??? so check what is your table name: movie ? or movies ? and better is use alias like: SELECT mov.title, gen.name FROM movie mov LEFT OUTER JOIN genres gen ON mov.genre_id=gen.id WHERE mov.genre_id IS NOT NULL;

James Anwyl
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James Anwyl
Full Stack JavaScript Techdegree Graduate 49,960 Points
James Anwyl
.a{fill-rule:evenodd;}techdegree seal-36
James Anwyl
Full Stack JavaScript Techdegree Graduate 49,960 Points

You don't need the WHERE clause as you are trying to include all movies (even the ones without a genre_ID). By saying WHERE genre_id IS NOT NULL you are excluding entries that don't have a genre_ID (i.e the genre_id = NULL). We want to include them, so just do:

SELECT movies.title, genres.name FROM movies LEFT OUTER JOIN genres ON movies.genre_id = genres.id;

Hope this makes sense :)

Taylor Rogers
Taylor Rogers
806 Points
Taylor Rogers
Taylor Rogers
806 Points

Okay it worked thank you!!