SELECT names

name	continent
Afghanistan	Asia
Albania	Europe
Algeria	Africa
Andorra	Europe
Angola	Africa
....

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Pattern Matching Strings

This tutorial uses the LIKE operator to check names. We will be using the SELECT command on the table world:

1.

You can use WHERE name LIKE 'B%' to find the countries that start with "B".

• The % is a wild-card it can match any characters

Find the country that start with Y

SELECT name FROM world
  WHERE name LIKE 'F%'

SELECT name FROM world
  WHERE name LIKE 'Y%'

SELECT name FROM world WHERE name LIKE 'F%' Submit SQLrestore default

result

2.

Find the countries that end with y

SELECT name FROM world
  WHERE name LIKE 'T%'

SELECT name FROM world
  WHERE name LIKE '%y'

SELECT name FROM world WHERE name LIKE 'T%' Submit SQLrestore default

result

3.

Luxembourg has an x - so does one other country. List them both.

Find the countries that contain the letter x

SELECT name FROM world
  WHERE name LIKE 'T%'

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

SELECT name FROM world WHERE name LIKE 'T%' Submit SQLrestore default

result

4.

Iceland, Switzerland end with land - but are there others?

Find the countries that end with land

SELECT name FROM world
  WHERE name LIKE 'T%'

SELECT name FROM world
  WHERE name LIKE '%land'

SELECT name FROM world WHERE name LIKE 'T%' Submit SQLrestore default

result

5.

Columbia starts with a C and ends with ia - there are two more like this.

Find the countries that start with C and end with ia

SELECT name FROM world
  WHERE name LIKE 'T%'

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

SELECT name FROM world WHERE name LIKE 'T%' Submit SQLrestore default

result

6.

Greece has a double e - who has a double o?

Find the country that has oo in the name

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

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

SELECT name FROM world WHERE name LIKE '%ee%' Submit SQLrestore default

result

7.

Bahamas has three a - who else?

Find the countries that have three or more a in the name

SELECT name FROM world
  WHERE name LIKE 'T%'

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

SELECT name FROM world WHERE name LIKE 'T%' Submit SQLrestore default

result

8.

India and Angola have an n as the second character. You can use the underscore as a single character wildcard.

SELECT name FROM world
 WHERE name LIKE '_n%'
ORDER BY name

Find the countries that have "t" as the second character.

SELECT name FROM world
 WHERE name LIKE '_n%'
ORDER BY name

SELECT name FROM world
 WHERE name LIKE '_t%'
ORDER BY name

SELECT name FROM world WHERE name LIKE '_n%' ORDER BY name Submit SQLrestore default

result

9.

Lesotho and Moldova both have two o characters separated by two other characters.

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

SELECT name FROM world
 WHERE name LIKE '_n%'

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

SELECT name FROM world WHERE name LIKE '_n%' Submit SQLrestore default

result

10.

Cuba and Togo have four characters names.

Find the countries that have exactly four characters.

SELECT name FROM world
 WHERE name LIKE 'Cu%'

SELECT name FROM world
 WHERE name LIKE '____'

SELECT name FROM world WHERE name LIKE 'Cu%' Submit SQLrestore default

result

Play Find the Duplicates

Find the Duplicates Game

Harder Questions

Well done for getting this far.

The next questions are optional and only for students who are finding the basic questions too easy.

11.

The capital of Luxembourg is Luxembourg. Show all the countries where the capital is the same as the name of the country

Find the country where the name is the capital city.

SELECT name, capital, continent
  FROM world
 WHERE name LIKE '%x%'

SELECT name FROM world
 WHERE name = capital

SELECT name, capital, continent FROM world WHERE name LIKE '%x%' Submit SQLrestore default

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12.

The capital of Mexico is Mexico City. Show all the countries where the capital has the country together with the word "City".

Find the country where the capital is the country plus "City".

The concat function

The function concat is short for concatenate - you can use it to combine two or more strings.

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

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

SELECT name, concat(name, 'town') FROM world WHERE name LIKE '%ina%'Submit SQLrestore default

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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, '%')

Submit SQLrestore default

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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, '_%')

Submit SQLrestore default

result

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.

select name, replace(capital,name,'')
from world
where capital LIKE concat(name,'_%')

Submit SQLrestore default

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