typo

README.md

@@ -8,7 +8,7 @@ In this project, we'll continue to use <a href="https://postgres.devmountain.com
 
 ### Summary
 
-When creating tables we can specify a column as having a foreign key. The datatype of our column must match the datatype of the column we are linking to. The most common foriegn key is a primary key which is usually an integer.
+When creating tables we can specify a column as having a foreign key. The datatype of our column must match the datatype of the column we are linking to. The most common foreign key is a primary key which is usually an integer.
 
 ### Instructions 
 

afternoon.sql

@@ -0,0 +1,73 @@
+--answers to read me file
+
+--syntax hint
+
+SELECT [Column names] 
+FROM [table] [abbv]
+JOIN [table2] [abbv2] ON abbv.prop = abbv2.prop WHERE [Conditions];
+
+SELECT a.name, b.name FROM some_table a JOIN another_table b ON a.some_id = b.some_id;
+SELECT a.name, b.name FROM some_table a JOIN another_table b ON a.some_id = b.some_id WHERE b.email = 'e@mail.com';
+
+--Get all invoices where the unit_price on the invoice_line is greater than $0.99.
+
+SELECT *
+FROM invoice i
+JOIN invoice_line il ON il.invoice_id = i.invoice_id
+WHERE il.unit_price > 0.99;
+
+--Get the invoice_date, customer first_name and last_name, and total from all invoices.
+
+SELECT i.invoice_date, c.first_name, c.last_name, i.total
+FROM invoice i
+JOIN customer c ON i.customer_id = c.customer_id;
+
+--Get the customer first_name and last_name and the support rep's first_name and last_name from all customers.
+--Support reps are on the employee table.
+
+select customer.first_name, customer.last_name, employee.first_name, employee.last_name from customer
+join employee on employee.employee_id = customer.support_rep_id;
+
+--Get the album title and the artist name from all albums.
+
+SELECT al.title, ar.name
+FROM album al
+JOIN artist ar ON al.artist_id = ar.artist_id;
+
+--Get all playlist_track track_ids where the playlist name is Music.
+
+select playlist_track.track_id 
+from playlist_track
+join playlist on (playlist.playlist_id = playlist_track.playlist_id)
+where playlist.name = 'Music';
+
+
+--Get all track names for playlist_id 5.
+
+select track.name 
+from track 
+join playlist_track on (playlist_track.track_id = track.track_id)
+where playlist_track.track_id = 5;
+
+
+--Get all track names and the playlist name that they're on ( 2 joins ).
+
+select track.name, playlist.name 
+from track
+join playlist_track on (playlist_track.track_id = track.track_id)
+join playlist on (playlist_track.playlist_id = playlist.playlist_id);
+
+--Get all track names and album titles that are the genre Alternative & Punk ( 2 joins )
+
+select track.name, album.title 
+from track 
+join album on (album.album_id = track.album_id)
+join genre on (genre.genre_id = track.genre_id)
+where genre.name = 'Alternative & Punk';
+
+ --black diamond
+ --Get all tracks on the playlist(s) called Music and show their name, genre name, album name, and artist name.
+--At least 5 joins.
+
+
+