 
-- create
CREATE TABLE airbnb_listings (
  id INTEGER PRIMARY KEY,
  city TEXT NOT NULL,
  country TEXT NOT NULL,
  number_of_rooms INTEGER NOT NULL, 
  year_listed INTEGER NOT NULL
);

-- insert
INSERT INTO airbnb_listings VALUES (0001, 'Paris', 'France', 5, 2018);
INSERT INTO airbnb_listings VALUES (0002, 'Tokyo', 'Japan', 2, 2017);
INSERT INTO airbnb_listings VALUES (0003, 'New York', 'USA', 2, 2022);


-- QUERYING TABLES 

-- Get all the columns from a table 
SELECT * 
FROM airbnb_listings;


-- Return the city column from the table
-- SELECT city 
-- FROM airbnb_listings;


-- Get the city and year_listed columns from the table
-- SELECT city, year_listed
-- from airbnb_listings;


-- Get the listing id, city, ordered by the number_of_rooms in ascending order
-- SELECT id, city
-- FROM airbnb_listings
-- ORDER BY number_of_rooms ASC;


-- Get the listing id, city, ordered by the number_of_rooms in descending order
-- SELECT id, city
-- FROM airbnb_listings
-- ORDER BY number_of_rooms DESC;


-- Get the first 5 rows from the airbnb_listings table
-- SELECT * 
-- FROM airbnb_listings
-- LIMIT 5;


-- Get a unique list of cities wehre there are listings 
-- SELECT DISTINCT city
-- FROM airbnb_listings;





-- FILTERING DATA 

-- Get all the listings wehre number_of_rooms is more or equal to 3
-- SELECT * 
-- FROM airbnb_listings
-- WHERE number_of_rooms >= 3;


-- Get all the listings where number_of_rooms is more than 3
-- SELECT *
-- FROM airbnb_listings
-- WHERE number_of_rooms > 3;


-- Get all the listings where number_of_rooms is exactly equal to 2
-- SELECT *
-- FROM airbnb_listings
-- WHERE number_of_rooms = 2;


-- Get all the listings with 3 to 6 rooms
-- SELECT *
-- FROM airbnb_listings
-- WHERE number_of_rooms BETWEEN 3 AND 6;


-- Get all the listings that are based in 'Paris'
-- SELECT * 
-- FROM airbnb_listings
-- WHERE city = 'Paris';


-- Get the listings based in the 'USA' and in 'France'
-- SELECT * 
-- FROM airbnb_listings
-- WHERE country IN ('USA', 'France');


-- Get all the listings where the country starts with 'j' and wehre the country does not end in 't'
-- SELECT *
-- FROM airbnb_listings
-- WHERE country LIKE 'j%' AND country NOT LIKE '%t';


-- Get all the listings in 'Paris' wehre number_of_rooms is bigger than 3  
-- SELECT * 
-- FROM airbnb_listings
-- WHERE city = 'Paris' AND number_of_rooms > 3;


-- Get all the listings in 'Paris' OR the ones that were listed after 2012
-- SELECT *
-- FROM airbnb_listings
-- WHERE city = 'Paris' OR year_listed > 2012


-- Return the listings where number_of_rooms is missing 
-- SELECT *
-- FROM airbnb_listings
-- WHERE number_of_rooms IS NULL;


-- Return the listings wehre number_of_rooms is not missing 
-- SELECT * 
-- FROM airbnb_listings
-- WHERE number_of_rooms IS NOT NULL;







-- AGGREGATING DATA 

-- Get the total number of rooms available across all listings 
-- SELECT SUM(number_of_rooms)
-- FROM airbnb_listings;


-- Get the average number of rooms per listing across all listings 
-- SELECT AVG(number_of_rooms)
-- FROM airbnb_listings;


-- Get the listing with the highest number of rooms across all listings 
-- SELECT MAX(number_of_rooms)
-- FROM airbnb_listings;


-- Get the total number of rooms for each country
-- SELECT country, SUM(number_of_rooms)
-- FROM airbnb_listings
-- GROUP BY country;


-- Get the average number of rooms for each country
-- SELECT country, AVG(number_of_rooms)
-- FROM airbnb_listings
-- GROUP BY country;


-- For each country, get the average number of rooms per listing, sorted by ascending order 
-- SELECT country, AVG(number_of_rooms) AS avg_rooms
-- FROM airbnb_listings
-- GROUP BY country
-- ORDER BY avg_rooms ASC;


-- For Japan and the USA, get the average numbner of rooms per listing in each country
-- SELECT country, AVG(number_of_rooms)
-- FROM airbnb_listings
-- WHERE country IN ('USA', 'JAPAN')
-- GROUP BY country;


-- Get the number of cities per country, where there are listings 
-- SELECT country, COUNT(city) AS number_of_cities 
-- FROM airbnb_listings
-- GROUP BY country;


-- Get all the years where there were more than 100 listings per year 
-- SELECT year_listed
-- FROM airbnb_listings
-- GROUP BY year_listed
-- HAVING COUNT(year_listed) > 100;

created 1 year ago by Brandon Fernando

MySQL online editor

Write, Run & Share MySQL queries online using OneCompiler's MySQL online editor and compiler for free. It's one of the robust, feature-rich online editor and compiler for MySQL. Getting started with the OneCompiler's MySQL editor is really simple and pretty fast. The editor shows sample boilerplate code when you choose language as 'MySQL' and start writing queries to learn and test online without worrying about tedious process of installation.

About MySQL

MySQL is a open-source, free and very popular relational database management system which is developed, distributed and supported by Oracle corporation.

Key Features:

Open-source relational database management systems.
Reliable, very fast and easy to use database server.
Works on client-server model.
Highly Secure and Scalable
High Performance
High productivity as it uses stored procedures, triggers, views to write a highly productive code.
Supports large databases efficiently.
Supports many operating systems like Linux*,CentOS*, Solaris*,Ubuntu*,Windows*, MacOS*,FreeBSD* and others.

Syntax help

Commands

1. CREATE

CREATE TABLE table_name (
                column1 datatype,
                column2 datatype,
                ....);

Example

CREATE TABLE EMPLOYEE (
  empId INTEGER PRIMARY KEY,
  name TEXT NOT NULL,
  dept TEXT NOT NULL
);

2. ALTER

ALTER TABLE Table_name ADD column_name datatype;

Example

INSERT INTO EMPLOYEE VALUES (0001, 'Dave', 'Sales');

3. TRUNCATE

TRUNCATE table table_name;

4. DROP

DROP TABLE table_name;

5. RENAME

RENAME TABLE table_name1 to new_table_name1;

6. COMMENT

Single-Line Comments:

 --Line1;

Multi-Line comments:

   /* Line1,
   Line2 */

DML Commands

1. INSERT

INSERT INTO table_name (column1, column2, column3, ...) VALUES (value1, value2, value3, ...);

Note: Column names are optional.

Example

INSERT INTO EMPLOYEE VALUES (0001, 'Ava', 'Sales');

2. SELECT

SELECT column1, column2, ...
FROM table_name
[where condition];

Example

SELECT * FROM EMPLOYEE where dept ='sales';

3. UPDATE

UPDATE table_name
SET column1 = value1, column2 = value2, ...
WHERE condition;

Example

UPDATE EMPLOYEE SET dept = 'Sales' WHERE empId='0001';

4. DELETE

DELETE FROM table_name where condition;

Example

DELETE from EMPLOYEE where empId='0001';

Indexes

1. CREATE INDEX

  CREATE INDEX index_name on table_name(column_name);

To Create Unique index:

  CREATE UNIQUE INDEX index_name on table_name(column_name);

2. DROP INDEX

DROP INDEX index_name ON table_name;

Views

1. Create a View

Creating a View:
CREATE VIEW View_name AS 
Query;

2. How to call view

SELECT * FROM View_name;

3. Altering a View

ALTER View View_name AS 
Query;

4. Deleting a View

DROP VIEW View_name;

Triggers

1. Create a Trigger

CREATE TRIGGER trigger_name trigger_time trigger_event
    ON tbl_name FOR EACH ROW [trigger_order] trigger_body
/* where
trigger_time: { BEFORE | AFTER }
trigger_event: { INSERT | UPDATE | DELETE }
trigger_order: { FOLLOWS | PRECEDES } */

2. Drop a Trigger

DROP TRIGGER [IF EXISTS] trigger_name;

Stored Procedures

1. Create a Stored Procedure

CREATE PROCEDURE sp_name(p1 datatype)
BEGIN
/*Stored procedure code*/
END;

2. How to call Stored procedure

CALL sp_name;

3. How to delete stored procedure

DROP PROCEDURE sp_name;

Joins

1. INNER JOIN

SELECT * FROM TABLE1 INNER JOIN TABLE2 where condition;

2. LEFT JOIN

SELECT * FROM TABLE1 LEFT JOIN TABLE2 ON condition;

3. RIGHT JOIN

SELECT * FROM TABLE1 RIGHT JOIN TABLE2 ON condition;

4. CROSS JOIN

SELECT select_list from TABLE1 CROSS JOIN TABLE2;