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Software ==>	Postgres SQL (35 exercises)
Topic ==>	More exotic joins (2 exercises)
Level ==>	Relatively easy
Subject ==>	PostgreSQL training

Use outer joins to show all tours (even those with no assocated albums)

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If you don't have a copy of the music_01 database, first follow the instructions at the following link to create it: https://www.wiseowl.co.uk/postgres/exercises/postgres-sql/using-postgres/5350/

Write a query to return the following columns from the tour table, making a note of how many rows the query returns:

The 99 tours in alphabetical order.

Use an inner join to add the Album table to the query, using the Album_ID columns to join the tables.

Twelve tours should have disappeared from the list.

Change the type of join so that your query returns every row from the tour table.

If you've listed the Tour table first in your FROM clause, it will be on the left hand side of the join.

Replace the Album_ID column in the SELECT list with the Title column from the Album table.

If you scroll down enough you'll see some of the album titles are null.

Add a criteria to your query to pick out only those tours where the corresponding album_id field is null:

The 12 tours with no corresponding albums.

Save the script as Taylor missing a trick.sql and then close it down.

You can find other training resources for the subject of this exercise here:

PostgreSQL classes

You can also book hourly online consultancy for your time zone with one of our 7 expert trainers!

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EXERCISE TOPIC

POSTGRESQL EXERCISES

POSTGRES SQL EXERCISES

Use outer joins to show all tours (even those with no assocated albums)

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