01-Pattern-Matching.sql

/*
Some pattern matching queries
https://sqlzoo.net/wiki/SELECT_names
*/

/*
  1. Find the countries that start with Y
*/

SELECT name FROM world
  WHERE name LIKE 'Y%'


/*
  2. Find the countries that end with y
*/

SELECT name FROM world
  WHERE name LIKE '%y'


/*
  3. Find the countries that contain the letter x
*/

SELECT name FROM world
  WHERE name LIKE '%x%'


/*
  4. Find the countries that end with land
*/

SELECT name FROM world
  WHERE name LIKE '%land'


/*
  5. Find the countries that start with C and end with ia
*/

SELECT name FROM world
  WHERE name LIKE 'C%ia'


/*
  6. Find the country that has oo in the name
*/

SELECT name FROM world
  WHERE name LIKE '%oo%'


/*
  7. Find the countries that have three or more a in the name
*/

SELECT name FROM world
  WHERE name LIKE '%a%a%a%'


/*
  8. Find the countries that have "t" as the second character.
*/

SELECT name FROM world
  WHERE name LIKE '_t%'


/*
  9. Find the countries that have two "o" characters separated by two others.
*/

SELECT name FROM world
  WHERE name LIKE '%o__o%'


/*
  10. Find the countries that have exactly four characters.
*/

SELECT name FROM world
  WHERE name LIKE '____'


/*
  11. Find the country where the name is the capital city.
*/

SELECT name FROM world
  WHERE name = capital


/*
  12. Find the country where the capital is the country plus "City".
*/

SELECT name FROM world
  WHERE capital = concat(name, ' City')


/*
  13. Find the capital and the name where the capital includes the name of the country.
*/

SELECT capital, name FROM world
  WHERE capital LIKE concat('%', name, '%')

/*
  14. Find the capital and the name where the capital is an extension of name of the country.
      You should include Mexico City as it is longer than Mexico.
      You should not include Luxembourg as the capital is the same as the country. 
*/

SELECT capital, name FROM world
  WHERE capital LIKE concat('%', name, '%') AND capital <> name

/*
  15. The capital of Monaco is Monaco-Ville: this is the name Monaco and the extension is -Ville.
      Show the name and the extension where the capital is a proper (non-empty) extension of name of the country.
      You can use the SQL function REPLACE (https://sqlzoo.net/wiki/REPLACE). 
*/

SELECT name, REPLACE(capital, name, '') AS extention
FROM world
WHERE capital LIKE concat('%', name, '%') AND capital <> name