Just a refresher on SQL
$ sudo apt update
$ sudo apt install mysql-server
...
$ mysql --version
mysql Ver 8.0.25-0ubuntu0.20.04.1 for Linux on x86_64 ((Ubuntu))
$
$ service mysql start
Write a script that lists all databases of your MySQL server.
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 0-list_databases.sql | mysql -hlocalhost -uroot -p
Enter password:
Database
hbtn_0c_0
information_schema
mysql
performance_schema
sys
Write a script that creates the database hbtn_0c_0 in your MySQL server.
- If the database hbtn_0c_0 already exists, your script should not fail
- You are not allowed to use the SELECT or SHOW statements
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 1-create_database_if_missing.sql | mysql -hlocalhost -uroot -p
Enter password:
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 0-list_databases.sql | mysql -hlocalhost -uroot -p
Ener password:
Database
information_schema
hbtn_0c_0
mysql
performance_schema
Write a script that deletes the database hbtn_0c_0 in your MySQL server.
- If the database hbtn_0c_0 doesn’t exist, your script should not fail
- You are not allowed to use the SELECT or SHOW statements
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 0-list_databases.sql | mysql -hlocalhost -uroot -p
Enter password:
Database
hbtn_0c_0
information_schema
mysql
performance_schema
sys
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 2-remove_database.sql | mysql -hlocalhost -uroot -p
Enter password:
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 0-list_databases.sql | mysql -hlocalhost -uroot -p
Enter password:
Database
information_schema
mysql
performance_schema
sys
Write a script that lists all the tables of a database in your MySQL server.
- The database name will be passed as argument of mysql command (in the following example: mysql is the name of the database)
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 3-list_tables.sql | mysql -hlocalhost -uroot -p mysql
Enter password:
Tables_in_mysql
columns_priv
component
db
default_roles
engine_cost
func
general_log
global_grants
gtid_executed
help_category
help_keyword
help_relation
help_topic
innodb_index_stats
innodb_table_stats
password_history
plugin
procs_priv
proxies_priv
replication_asynchronous_connection_failover
replication_asynchronous_connection_failover_managed
role_edges
server_cost
servers
slave_master_info
slave_relay_log_info
slave_worker_info
slow_log
tables_priv
time_zone
time_zone_leap_second
time_zone_name
time_zone_transition
time_zone_transition_type
user
Write a script that creates a table called first_table in the current database in your MySQL server.
- first_table description:
- id INT
- name VARCHAR(256)
- The database name will be passed as an argument of the mysql command
- If the table first_table already exists, your script should not fail
- You are not allowed to use the SELECT or SHOW statements
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 4-first_table.sql | mysql -hlocalhost -uroot -p hbtn_0c_0
Enter password:
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 3-list_tables.sql | mysql -hlocalhost -uroot -p hbtn_0c_0
Enter password:
Tables_in_hbtn_0c_0
first_table
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$
Write a script that prints the full description of the table first_table from the database hbtn_0c_0 in your MySQL server.
- The database name will be passed as an argument of the mysql command
- You are not allowed to use the DESCRIBE or EXPLAIN statements
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 5-full_table.sql | mysql -hlocalhost -uroot -p hbtn_0c_0
Enter password:
Table Create Table
first_table CREATE TABLE `first_table` (\n `id` int DEFAULT NULL,\n `name` varchar(256) DEFAULT NULL\n) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$
Write a script that lists all rows of the table first_table from the database hbtn_0c_0 in your MySQL server.
- All fields should be printed
- The database name will be passed as an argument of the mysql command
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 6-list_values.sql | mysql -hlocalhost -uroot -p hbtn_0c_0
Enter password:
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$
Write a script that inserts a new row in the table first_table (database hbtn_0c_0) in your MySQL server.
- New row:
- id = 89
- name = Best School
- The database name will be passed as an argument of the mysql command
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 7-insert_value.sql | mysql -hlocalhost -uroot -p hbtn_0c_0
Enter password:
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 6-list_values.sql | mysql -hlocalhost -uroot -p hbtn_0c_0
Enter password:
id name
89 Best School
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 7-insert_value.sql | mysql -hlocalhost -uroot -p hbtn_0c_0
Enter password:
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 7-insert_value.sql | mysql -hlocalhost -uroot -p hbtn_0c_0
Enter password:
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 6-list_values.sql | mysql -hlocalhost -uroot -p hbtn_0c_0
Enter password:
id name
89 Best School
89 Best School
89 Best School
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$
Write a script that displays the number of records with id = 89 in the table first_table of the database hbtn_0c_0 in your MySQL server.
- The database name will be passed as an argument of the mysql command
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 8-count_89.sql | mysql -hlocalhost -uroot -p hbtn_0c_0 | tail -1
Enter password:
3
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$
Write a script that creates a table second_table in the database hbtn_0c_0 in your MySQL server and add multiples rows.
- second_table description:
- id INT
- name VARCHAR(256)
- score INT
- The database name will be passed as an argument to the mysql command
- If the table second_table already exists, your script should not fail
- You are not allowed to use the SELECT and SHOW statements
- Your script should create these records:
- id = 1, name = “John”, score = 10
- id = 2, name = “Alex”, score = 3
- id = 3, name = “Bob”, score = 14
- id = 4, name = “George”, score = 8
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 9-full_creation.sql | mysql -hlocalhost -uroot -p hbtn_0c_0
Enter password:
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$
Write a script that lists all records of the table second_table of the database hbtn_0c_0 in your MySQL server.
- Results should display both the score and the name (in this order)
- Records should be ordered by score (top first)
- The database name will be passed as an argument of the mysql command
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 10-top_score.sql | mysql -hlocalhost -uroot -p hbtn_0c_0
Enter password:
score name
14 Bob
10 John
8 George
3 Alex
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$
Write a script that lists all records with a score >= 10 in the table second_table of the database hbtn_0c_0 in your MySQL server.
- Results should display both the score and the name (in this order)
- Records should be ordered by score (top first)
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 11-best_score.sql | mysql -hlocalhost -uroot -p hbtn_0c_0
Enter password:
score name
14 Bob
10 John
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$
Write a script that updates the score of Bob to 10 in the table second_table.
- You are not allowed to use Bob’s id value, only the name field
- The database name will be passed as an argument of the mysql command
- The database name will be passed as an argument of the mysql command
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 12-no_cheating.sql | mysql -hlocalhost -uroot -p hbtn_0c_0
Enter password:
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 10-top_score.sql | mysql -hlocalhost -uroot -p hbtn_0c_0
Enter password:
score name
10 John
10 Bob
8 George
3 Alex
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$
Write a script that removes all records with a score <= 5 in the table second_table of the database hbtn_0c_0 in your MySQL server.
- The database name will be passed as an argument of the mysql command
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 13-change_class.sql | mysql -hlocalhost -uroot -p hbtn_0c_0
Enter password:
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 10-top_score.sql | mysql -hlocalhost -uroot -p hbtn_0c_0
Enter password:
score name
10 John
10 Bob
8 George
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$
Write a script that computes the score average of all records in the table second_table
of the database hbtn_0c_0
in your MySQL server.
- The result column name should be average
- The database name will be passed as an argument of the mysql command
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 14-average.sql | mysql -hlocalhost -uroot -p hbtn_0c_0
Enter password:
average
9.3333
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$
Write a script that lists the number of records with the same score in the table second_table
of the database hbtn_0c_0
in your MySQL server.
- The result should display:
- the score
- the number of records for this score with the label number
- The list should be sorted by the number of records (descending)
- The database name will be passed as an argument to the mysql command
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 15-groups.sql | mysql -hlocalhost -uroot -p hbtn_0c_0
Enter password:
score number
10 2
8 1
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$
Write a script that lists all records of the table second_table
of the database hbtn_0c_0
in your MySQL server.
- Don’t list rows without a name value
- Results should display the score and the name (in this order)
- Records should be listed by descending score
- The database name will be passed as an argument to the mysql command
In this example, new data have been added to the table second_table.
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 16-no_link.sql | mysql -hlocalhost -uroot -p hbtn_0c_0
Enter password:
score name
18 Aria
12 Aria
10 John
10 Bob
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$
Write a script that converts hbtn_0c_0 database to UTF8 (utf8mb4, collate utf8mb4_unicode_ci) in your MySQL server.
You need to convert all of the following to UTF8:
- Database hbtn_0c_0
- Table first_table
- Field name in first_table
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 100-move_to_utf8.sql | mysql -hlocalhost -uroot -p
Enter password:
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 5-full_table.sql | mysql -hlocalhost -uroot -p hbtn_0c_0
Enter password:
Table Create Table
first_table CREATE TABLE `first_table` (\n `id` int(11) DEFAULT NULL,\n `name` varchar(256) COLLATE utf8mb4_unicode_ci DEFAULT NULL\n) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$
Write a script that displays the average temperature (Fahrenheit) by city ordered by temperature (descending).
For this task and subsequent tasks, we need to download a table dump file and import it into the hbtn_0c_0 database. In order to achieve that, we need to do two steps to achieve our goal.
First step
Download the dump file using curl:
bash curl -o temperatures.sql "link to the dump file"
Second step Import the table into the database
mysql -u your_username -p your_database_name < table_dump.sql
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 101-avg_temperatures.sql | mysql -hlocalhost -uroot -p hbtn_0c_0
Enter password:
city avg_temp
Chandler 72.8627
Gilbert 71.8088
Pismo beach 71.5147
San Francisco 71.4804
Sedona 70.7696
Phoenix 70.5882
Oakland 70.5637
Sunnyvale 70.5245
Chicago 70.4461
San Diego 70.1373
Glendale 70.1225
Sonoma 70.0392
Yuma 69.3873
San Jose 69.2990
Tucson 69.0245
Joliet 68.6716
Naperville 68.1029
Tempe 67.0441
Peoria 66.5392
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$
Write a script that displays the top 3 of cities temperature during July and August ordered by temperature (descending)
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 102-top_city.sql | mysql -hlocalhost -uroot -p hbtn_0c_0
Enter password:
city avg_temp
Naperville 76.9412
San Diego 73.7941
Sunnyvale 73.2353
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$
Write a script that displays the max temperature of each state (ordered by State name).
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$ cat 103-max_state.sql | mysql -hlocalhost -uroot -p hbtn_0c_0
Enter password:
state max_temp
AZ 110
CA 110
IL 110
vagrant@ubuntu-focal:~/ALX_SQL_Refresher$