From d6b99cc0d171fb1581b9ad643f7c8c62bf063671 Mon Sep 17 00:00:00 2001
From: Sai-Nandan-Desetti
 <80631906+Sai-Nandan-Desetti@users.noreply.github.com>
Date: Fri, 26 May 2023 22:29:40 +0530
Subject: [PATCH 1/8] Update 7.sql

No hardcoding the ids.
---
 solutions/7.sql | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/solutions/7.sql b/solutions/7.sql
index 64a4164..101a839 100644
--- a/solutions/7.sql
+++ b/solutions/7.sql
@@ -3,6 +3,18 @@
   SELECT * FROM albums where release_year IS NULL;
 */
 
+/*
 UPDATE albums
 SET release_year = 1986
-WHERE id = 4;
\ No newline at end of file
+WHERE id = 4;
+*/
+
+/* 
+The above solution doesn't seem practical
+if you have many different ids whose release_year IS NULL
+*/
+
+UPDATE albums,
+	(SELECT id FROM albums WHERE release_year IS NULL) AS not_yet_released
+SET albums.release_year = 1986
+WHERE albums.id = not_yet_released.id;

From ca24e4419a5a9604b406da6b49c9a2096fa844e8 Mon Sep 17 00:00:00 2001
From: Sai-Nandan-Desetti
 <80631906+Sai-Nandan-Desetti@users.noreply.github.com>
Date: Fri, 26 May 2023 22:40:44 +0530
Subject: [PATCH 2/8] Update 5.sql

Using non-aggregate columns in SELECT with the default modes in MySQL Workbench.
---
 solutions/5.sql | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/solutions/5.sql b/solutions/5.sql
index 6a5ebff..8f2cba4 100644
--- a/solutions/5.sql
+++ b/solutions/5.sql
@@ -1,5 +1,21 @@
+/*
 SELECT bands.name AS 'Band Name'
 FROM bands
 LEFT JOIN albums ON bands.id = albums.band_id
 GROUP BY albums.band_id
-HAVING COUNT(albums.id) = 0;
\ No newline at end of file
+HAVING COUNT(albums.id) = 0;
+*/
+
+/*
+The given solution throws an error:
+Error Code: 1055. Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'record_company.bands.name' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by
+*/
+SELECT bands.name AS 'Band Name'
+FROM bands 
+INNER JOIN (
+	SELECT bands.id as id
+	FROM bands
+	LEFT JOIN albums ON bands.id = albums.band_id
+	WHERE albums.band_id IS NULL
+) AS bands_with_no_albums
+ON bands.id = bands_with_no_albums.id;

From 96c4b64af0a11d15787de908bb17afb59515feaa Mon Sep 17 00:00:00 2001
From: Sai-Nandan-Desetti
 <80631906+Sai-Nandan-Desetti@users.noreply.github.com>
Date: Fri, 26 May 2023 23:49:23 +0530
Subject: [PATCH 3/8] Update 9.sql

---
 solutions/9.sql | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/solutions/9.sql b/solutions/9.sql
index b2f041e..d3dea6b 100644
--- a/solutions/9.sql
+++ b/solutions/9.sql
@@ -4,6 +4,7 @@
   ORDER BY id DESC LIMIT 1;
 */
 
+/*
 DELETE FROM albums
 WHERE id = 19;
 
@@ -14,4 +15,22 @@ WHERE id = 19;
 */
 
 DELETE FROM bands
-WHERE id = 8;
\ No newline at end of file
+WHERE id = 8;
+*/
+
+/*
+No harcoding the id
+*/
+DELETE FROM albums
+WHERE albums.band_id
+IN (SELECT id FROM bands WHERE name = 'SSSPSN');
+
+SELECT * FROM albums;
+
+/*
+Note the apparently redundant but necessary use of the SELECT * subquery
+*/
+DELETE FROM bands
+WHERE id IN (SELECT * FROM (SELECT id FROM bands WHERE name = 'SSSPSN') AS to_delete);
+
+SELECT * FROM bands;

From 683c92ca0a68bc420187f3b9e4416a3230357a4a Mon Sep 17 00:00:00 2001
From: Sai-Nandan-Desetti
 <80631906+Sai-Nandan-Desetti@users.noreply.github.com>
Date: Fri, 26 May 2023 23:49:51 +0530
Subject: [PATCH 4/8] Update 9.sql

---
 solutions/9.sql | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/solutions/9.sql b/solutions/9.sql
index d3dea6b..135d959 100644
--- a/solutions/9.sql
+++ b/solutions/9.sql
@@ -7,6 +7,7 @@
 /*
 DELETE FROM albums
 WHERE id = 19;
+*/
 
 /* This is the query used to get the band id of the band added in #8 */
 /*
@@ -14,6 +15,7 @@ WHERE id = 19;
   ORDER BY id DESC LIMIT 1;
 */
 
+/*
 DELETE FROM bands
 WHERE id = 8;
 */

From e2ebd160f2033b06e0a0c5625fb98a3b65d2df7d Mon Sep 17 00:00:00 2001
From: Sai-Nandan-Desetti
 <80631906+Sai-Nandan-Desetti@users.noreply.github.com>
Date: Sat, 27 May 2023 00:27:46 +0530
Subject: [PATCH 5/8] Update 12.sql

---
 solutions/12.sql | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/solutions/12.sql b/solutions/12.sql
index 8beb83b..3a70d93 100644
--- a/solutions/12.sql
+++ b/solutions/12.sql
@@ -1,7 +1,24 @@
+/*
 SELECT
   bands.name AS 'Band',
   COUNT(songs.id) AS 'Number of Songs'
 FROM bands
 JOIN albums ON bands.id = albums.band_id
 JOIN songs ON albums.id = songs.album_id
-GROUP BY albums.band_id;
\ No newline at end of file
+GROUP BY albums.band_id;
+*/
+
+SELECT bands.name AS 'Band', songs_per_band AS 'Number of Songs'
+FROM bands
+INNER JOIN (
+	SELECT band_id, sum(albums_songs.songs_per_album) AS songs_per_band
+    FROM albums
+    INNER JOIN (
+		SELECT album_id, count(album_id) AS songs_per_album
+        FROM songs
+        GROUP BY album_id
+	) AS albums_songs
+    ON albums.id = albums_songs.album_id
+    GROUP BY band_id
+) AS bands_songs
+ON bands.id = bands_songs.band_id;

From 530f71b6f49a2fb2e213750641390e04f6a8262a Mon Sep 17 00:00:00 2001
From: Sai-Nandan-Desetti
 <80631906+Sai-Nandan-Desetti@users.noreply.github.com>
Date: Sat, 27 May 2023 00:28:58 +0530
Subject: [PATCH 6/8] Update 11.sql

---
 solutions/11.sql | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/solutions/11.sql b/solutions/11.sql
index 3c32272..b8ab0cc 100644
--- a/solutions/11.sql
+++ b/solutions/11.sql
@@ -1,7 +1,17 @@
+/*
 SELECT
   albums.name AS 'Album',
   albums.release_year AS 'Release Year',
   MAX(songs.length) AS 'Duration'
 FROM albums
 JOIN songs ON albums.id = songs.album_id
-GROUP BY songs.album_id;
\ No newline at end of file
+GROUP BY songs.album_id;
+*/
+
+SELECT albums.name AS 'Name', albums.release_year AS 'Release Year', longest_songs.duration AS 'Duration'
+FROM albums
+INNER JOIN (
+	SELECT album_id, max(length) AS duration FROM songs
+	GROUP BY album_id
+) AS longest_songs
+ON albums.id = longest_songs.album_id;

From a4ea375bf6e5cb642828e4bdc24ea4356f61fe51 Mon Sep 17 00:00:00 2001
From: Sai Nandan Desetti
 <80631906+Sai-Nandan-Desetti@users.noreply.github.com>
Date: Wed, 14 Jun 2023 15:25:55 +0530
Subject: [PATCH 7/8] Delete solutions directory

---
 solutions/1.sql  |  8 --------
 solutions/10.sql |  2 --
 solutions/11.sql | 17 -----------------
 solutions/12.sql | 24 ------------------------
 solutions/2.sql  |  2 --
 solutions/3.sql  |  4 ----
 solutions/4.sql  | 14 --------------
 solutions/5.sql  | 21 ---------------------
 solutions/6.sql  |  9 ---------
 solutions/7.sql  | 20 --------------------
 solutions/8.sql  | 11 -----------
 solutions/9.sql  | 38 --------------------------------------
 12 files changed, 170 deletions(-)
 delete mode 100644 solutions/1.sql
 delete mode 100644 solutions/10.sql
 delete mode 100644 solutions/11.sql
 delete mode 100644 solutions/12.sql
 delete mode 100644 solutions/2.sql
 delete mode 100644 solutions/3.sql
 delete mode 100644 solutions/4.sql
 delete mode 100644 solutions/5.sql
 delete mode 100644 solutions/6.sql
 delete mode 100644 solutions/7.sql
 delete mode 100644 solutions/8.sql
 delete mode 100644 solutions/9.sql

diff --git a/solutions/1.sql b/solutions/1.sql
deleted file mode 100644
index c599583..0000000
--- a/solutions/1.sql
+++ /dev/null
@@ -1,8 +0,0 @@
-CREATE TABLE songs (
-  id INT NOT NULL AUTO_INCREMENT,
-  name VARCHAR(255) NOT NULL,
-  length FLOAT NOT NULL,
-  album_id INT NOT NULL,
-  PRIMARY KEY (id),
-  FOREIGN KEY (album_id) REFERENCES albums(id)
-);
\ No newline at end of file
diff --git a/solutions/10.sql b/solutions/10.sql
deleted file mode 100644
index a6fb165..0000000
--- a/solutions/10.sql
+++ /dev/null
@@ -1,2 +0,0 @@
-SELECT AVG(length) as 'Average Song Duration'
-FROM songs;
\ No newline at end of file
diff --git a/solutions/11.sql b/solutions/11.sql
deleted file mode 100644
index b8ab0cc..0000000
--- a/solutions/11.sql
+++ /dev/null
@@ -1,17 +0,0 @@
-/*
-SELECT
-  albums.name AS 'Album',
-  albums.release_year AS 'Release Year',
-  MAX(songs.length) AS 'Duration'
-FROM albums
-JOIN songs ON albums.id = songs.album_id
-GROUP BY songs.album_id;
-*/
-
-SELECT albums.name AS 'Name', albums.release_year AS 'Release Year', longest_songs.duration AS 'Duration'
-FROM albums
-INNER JOIN (
-	SELECT album_id, max(length) AS duration FROM songs
-	GROUP BY album_id
-) AS longest_songs
-ON albums.id = longest_songs.album_id;
diff --git a/solutions/12.sql b/solutions/12.sql
deleted file mode 100644
index 3a70d93..0000000
--- a/solutions/12.sql
+++ /dev/null
@@ -1,24 +0,0 @@
-/*
-SELECT
-  bands.name AS 'Band',
-  COUNT(songs.id) AS 'Number of Songs'
-FROM bands
-JOIN albums ON bands.id = albums.band_id
-JOIN songs ON albums.id = songs.album_id
-GROUP BY albums.band_id;
-*/
-
-SELECT bands.name AS 'Band', songs_per_band AS 'Number of Songs'
-FROM bands
-INNER JOIN (
-	SELECT band_id, sum(albums_songs.songs_per_album) AS songs_per_band
-    FROM albums
-    INNER JOIN (
-		SELECT album_id, count(album_id) AS songs_per_album
-        FROM songs
-        GROUP BY album_id
-	) AS albums_songs
-    ON albums.id = albums_songs.album_id
-    GROUP BY band_id
-) AS bands_songs
-ON bands.id = bands_songs.band_id;
diff --git a/solutions/2.sql b/solutions/2.sql
deleted file mode 100644
index f7d1977..0000000
--- a/solutions/2.sql
+++ /dev/null
@@ -1,2 +0,0 @@
-SELECT bands.name AS 'Band Name'
-FROM bands;
\ No newline at end of file
diff --git a/solutions/3.sql b/solutions/3.sql
deleted file mode 100644
index 36500fb..0000000
--- a/solutions/3.sql
+++ /dev/null
@@ -1,4 +0,0 @@
-SELECT * FROM albums
-WHERE release_year IS NOT NULL
-ORDER BY release_year
-LIMIT 1;
\ No newline at end of file
diff --git a/solutions/4.sql b/solutions/4.sql
deleted file mode 100644
index 8df1baf..0000000
--- a/solutions/4.sql
+++ /dev/null
@@ -1,14 +0,0 @@
-
-/* This assummes all bands have a unique name */
-SELECT DISTINCT bands.name AS 'Band Name'
-FROM bands
-JOIN albums ON bands.id = albums.band_id;
-
-/* If bands do not have a unique name then use this query */
-/* 
-  SELECT bands.name AS 'Band Name'
-  FROM bands
-  JOIN albums ON bands.id = albums.band_id
-  GROUP BY albums.band_id
-  HAVING COUNT(albums.id) > 0;
-*/
\ No newline at end of file
diff --git a/solutions/5.sql b/solutions/5.sql
deleted file mode 100644
index 8f2cba4..0000000
--- a/solutions/5.sql
+++ /dev/null
@@ -1,21 +0,0 @@
-/*
-SELECT bands.name AS 'Band Name'
-FROM bands
-LEFT JOIN albums ON bands.id = albums.band_id
-GROUP BY albums.band_id
-HAVING COUNT(albums.id) = 0;
-*/
-
-/*
-The given solution throws an error:
-Error Code: 1055. Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'record_company.bands.name' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by
-*/
-SELECT bands.name AS 'Band Name'
-FROM bands 
-INNER JOIN (
-	SELECT bands.id as id
-	FROM bands
-	LEFT JOIN albums ON bands.id = albums.band_id
-	WHERE albums.band_id IS NULL
-) AS bands_with_no_albums
-ON bands.id = bands_with_no_albums.id;
diff --git a/solutions/6.sql b/solutions/6.sql
deleted file mode 100644
index aebd9dc..0000000
--- a/solutions/6.sql
+++ /dev/null
@@ -1,9 +0,0 @@
-SELECT
-  albums.name as Name,
-  albums.release_year as 'Release Year',
-  SUM(songs.length) as 'Duration'
-FROM albums
-JOIN songs on albums.id = songs.album_id
-GROUP BY songs.album_id
-ORDER BY Duration DESC
-LIMIT 1;
\ No newline at end of file
diff --git a/solutions/7.sql b/solutions/7.sql
deleted file mode 100644
index 101a839..0000000
--- a/solutions/7.sql
+++ /dev/null
@@ -1,20 +0,0 @@
-/* This is the query used to get the id */
-/*
-  SELECT * FROM albums where release_year IS NULL;
-*/
-
-/*
-UPDATE albums
-SET release_year = 1986
-WHERE id = 4;
-*/
-
-/* 
-The above solution doesn't seem practical
-if you have many different ids whose release_year IS NULL
-*/
-
-UPDATE albums,
-	(SELECT id FROM albums WHERE release_year IS NULL) AS not_yet_released
-SET albums.release_year = 1986
-WHERE albums.id = not_yet_released.id;
diff --git a/solutions/8.sql b/solutions/8.sql
deleted file mode 100644
index 8ed5185..0000000
--- a/solutions/8.sql
+++ /dev/null
@@ -1,11 +0,0 @@
-INSERT INTO bands (name)
-VALUES ('Favorite Band Name');
-
-/* This is the query used to get the band id of the band just added */
-/*
-  SELECT id FROM bands
-  ORDER BY id DESC LIMIT 1;
-*/
-
-INSERT INTO albums (name, release_year, band_id)
-VALUES ('Favorite Album Name', 2000, 8);
\ No newline at end of file
diff --git a/solutions/9.sql b/solutions/9.sql
deleted file mode 100644
index 135d959..0000000
--- a/solutions/9.sql
+++ /dev/null
@@ -1,38 +0,0 @@
-/* This is the query used to get the album id of the album added in #8 */
-/*
-  SELECT id FROM albums
-  ORDER BY id DESC LIMIT 1;
-*/
-
-/*
-DELETE FROM albums
-WHERE id = 19;
-*/
-
-/* This is the query used to get the band id of the band added in #8 */
-/*
-  SELECT id FROM bands
-  ORDER BY id DESC LIMIT 1;
-*/
-
-/*
-DELETE FROM bands
-WHERE id = 8;
-*/
-
-/*
-No harcoding the id
-*/
-DELETE FROM albums
-WHERE albums.band_id
-IN (SELECT id FROM bands WHERE name = 'SSSPSN');
-
-SELECT * FROM albums;
-
-/*
-Note the apparently redundant but necessary use of the SELECT * subquery
-*/
-DELETE FROM bands
-WHERE id IN (SELECT * FROM (SELECT id FROM bands WHERE name = 'SSSPSN') AS to_delete);
-
-SELECT * FROM bands;

From ed136919234f52125f5c4d3c5d7c1f830460b16a Mon Sep 17 00:00:00 2001
From: Sai Nandan Desetti
 <80631906+Sai-Nandan-Desetti@users.noreply.github.com>
Date: Wed, 14 Jun 2023 15:27:33 +0530
Subject: [PATCH 8/8] my solutions

---
 solutions/1.sql  |  9 +++++++++
 solutions/10.sql |  2 ++
 solutions/11.sql |  7 +++++++
 solutions/12.sql | 14 ++++++++++++++
 solutions/2.sql  |  2 ++
 solutions/3.sql  | 14 ++++++++++++++
 solutions/4.sql  | 21 +++++++++++++++++++++
 solutions/5.sql  | 29 +++++++++++++++++++++++++++++
 solutions/6.sql  |  9 +++++++++
 solutions/7.sql  |  4 ++++
 solutions/8.sql  |  9 +++++++++
 solutions/9.sql  | 11 +++++++++++
 12 files changed, 131 insertions(+)
 create mode 100644 solutions/1.sql
 create mode 100644 solutions/10.sql
 create mode 100644 solutions/11.sql
 create mode 100644 solutions/12.sql
 create mode 100644 solutions/2.sql
 create mode 100644 solutions/3.sql
 create mode 100644 solutions/4.sql
 create mode 100644 solutions/5.sql
 create mode 100644 solutions/6.sql
 create mode 100644 solutions/7.sql
 create mode 100644 solutions/8.sql
 create mode 100644 solutions/9.sql

diff --git a/solutions/1.sql b/solutions/1.sql
new file mode 100644
index 0000000..e4caa53
--- /dev/null
+++ b/solutions/1.sql
@@ -0,0 +1,9 @@
+CREATE TABLE songs
+(
+id int NOT NULL AUTO_INCREMENT,
+name varchar(255) NOT NULL,
+length float NOT NULL,
+album_id int NOT NULL,
+PRIMARY KEY(id),
+FOREIGN KEY(album_id) REFERENCES albums(id)
+);
\ No newline at end of file
diff --git a/solutions/10.sql b/solutions/10.sql
new file mode 100644
index 0000000..f9eaa72
--- /dev/null
+++ b/solutions/10.sql
@@ -0,0 +1,2 @@
+SELECT avg(length) AS 'Average Song Duration'
+FROM songs;
\ No newline at end of file
diff --git a/solutions/11.sql b/solutions/11.sql
new file mode 100644
index 0000000..47d13f3
--- /dev/null
+++ b/solutions/11.sql
@@ -0,0 +1,7 @@
+SELECT albums.name AS 'Name', albums.release_year AS 'Release Year', longest_songs.duration AS 'Duration'
+FROM albums
+INNER JOIN (
+	SELECT album_id, max(length) AS duration FROM songs
+	GROUP BY album_id
+) AS longest_songs
+ON albums.id = longest_songs.album_id;
\ No newline at end of file
diff --git a/solutions/12.sql b/solutions/12.sql
new file mode 100644
index 0000000..20997fd
--- /dev/null
+++ b/solutions/12.sql
@@ -0,0 +1,14 @@
+SELECT bands.name AS 'Band', songs_per_band AS 'Number of Songs'
+FROM bands
+INNER JOIN (
+	SELECT band_id, sum(albums_songs.songs_per_album) AS songs_per_band
+    FROM albums
+    INNER JOIN (
+		SELECT album_id, count(album_id) AS songs_per_album
+        FROM songs
+        GROUP BY album_id
+	) AS albums_songs
+    ON albums.id = albums_songs.album_id
+    GROUP BY band_id
+) AS bands_songs
+ON bands.id = bands_songs.band_id;
\ No newline at end of file
diff --git a/solutions/2.sql b/solutions/2.sql
new file mode 100644
index 0000000..771c6ad
--- /dev/null
+++ b/solutions/2.sql
@@ -0,0 +1,2 @@
+SELECT name AS 'Band Name'
+FROM bands;
\ No newline at end of file
diff --git a/solutions/3.sql b/solutions/3.sql
new file mode 100644
index 0000000..ecf07bd
--- /dev/null
+++ b/solutions/3.sql
@@ -0,0 +1,14 @@
+# My solution
+SELECT albums.*
+FROM albums
+INNER JOIN 
+(SELECT min(release_year) AS release_year FROM albums) AS oldest_album
+ON albums.release_year = oldest_album.release_year;
+
+
+# Given solution
+SELECT *
+FROM albums
+WHERE release_year IS NOT NULL
+ORDER BY release_year
+LIMIT 1;
\ No newline at end of file
diff --git a/solutions/4.sql b/solutions/4.sql
new file mode 100644
index 0000000..9f220d6
--- /dev/null
+++ b/solutions/4.sql
@@ -0,0 +1,21 @@
+# Solution 1
+/* Assumes that bands with different ids have different names. */
+SELECT DISTINCT(b.name) AS 'Band Name'
+FROM albums AS a
+INNER JOIN (bands AS b) ON a.band_id = b.id;
+
+
+/* The following two solutions don't assume that. */
+
+# Solution 2
+SELECT name AS 'Band Name'
+FROM bands
+INNER JOIN (SELECT DISTINCT(band_id) AS album_band_id FROM albums) AS bands_with_albums
+ON bands_with_albums.album_band_id = bands.id;
+
+
+# Solution 3
+SELECT name AS 'Band Name'
+FROM bands
+INNER JOIN (SELECT band_id FROM albums GROUP BY band_id) AS bands_with_albums
+ON bands_with_albums.band_id = bands.id;
diff --git a/solutions/5.sql b/solutions/5.sql
new file mode 100644
index 0000000..fd1afe0
--- /dev/null
+++ b/solutions/5.sql
@@ -0,0 +1,29 @@
+# Solution 1
+/* Assumes band names are unique */
+SELECT DISTINCT(bands.name) AS 'Band Name'
+FROM bands
+LEFT JOIN albums ON bands.id = albums.band_id
+WHERE albums.band_id IS NULL;
+
+
+/* No such assumption */
+# Solution 2
+SELECT bands.name AS 'Band Name'
+FROM bands 
+INNER JOIN (
+	SELECT bands.id as id
+	FROM bands
+	LEFT JOIN albums ON bands.id = albums.band_id
+	WHERE albums.band_id IS NULL
+) AS bands_with_no_albums
+ON bands.id = bands_with_no_albums.id;
+
+
+/*
+Note:
+There's an issue with the given solution: https://github.com/WebDevSimplified/Learn-SQL/issues/8
+The fellow who closed it must have changed the mode of SQL to something else.
+But it's been suggested to use full_group_by mode for SQL to avoid "inconsistencies".
+(Basically, find a different way to solve your problem
+ without using columns in SELECT that were not included in your GROUP BY.)
+*/
\ No newline at end of file
diff --git a/solutions/6.sql b/solutions/6.sql
new file mode 100644
index 0000000..6466d3b
--- /dev/null
+++ b/solutions/6.sql
@@ -0,0 +1,9 @@
+SELECT albums.name AS 'Name', albums.release_year AS 'Release Year', longest_album.Duration
+FROM (
+	SELECT album_id, sum(length) AS 'Duration'
+    FROM songs
+    GROUP BY album_id
+    ORDER BY Duration DESC
+    LIMIT 1
+) AS longest_album
+INNER JOIN albums ON longest_album.album_id = albums.id;
\ No newline at end of file
diff --git a/solutions/7.sql b/solutions/7.sql
new file mode 100644
index 0000000..e7a49c0
--- /dev/null
+++ b/solutions/7.sql
@@ -0,0 +1,4 @@
+UPDATE albums,
+	(SELECT id FROM albums WHERE release_year IS NULL) AS not_yet_released
+SET albums.release_year = 1986
+WHERE albums.id = not_yet_released.id;
\ No newline at end of file
diff --git a/solutions/8.sql b/solutions/8.sql
new file mode 100644
index 0000000..4ce9727
--- /dev/null
+++ b/solutions/8.sql
@@ -0,0 +1,9 @@
+INSERT INTO bands(name)
+VALUES ('SSSPSN');
+
+SELECT * FROM bands;
+
+INSERT INTO albums(name, release_year, band_id)
+VALUES ('Bhajans', 2009, 8);
+
+SELECT * FROM albums;
\ No newline at end of file
diff --git a/solutions/9.sql b/solutions/9.sql
new file mode 100644
index 0000000..e082a70
--- /dev/null
+++ b/solutions/9.sql
@@ -0,0 +1,11 @@
+DELETE FROM albums
+WHERE albums.band_id
+IN (SELECT id FROM bands WHERE name = 'SSSPSN');
+
+SELECT * FROM albums;
+
+
+DELETE FROM bands
+WHERE id IN (SELECT * FROM (SELECT id FROM bands WHERE name = 'SSSPSN') AS to_delete);
+
+SELECT * FROM bands;
\ No newline at end of file