11. Filtering by country

In the previous lesson, we’ve filtered records from the users table by country:

SELECT *
FROM users
WHERE
  country = 'de'

What questions are popping up in your head at this moment? Probably something similar to these:

  1. Why Germany has de value in the country column?
  2. How do we know the user’s country?
  3. What are country column values for other countries?

In this lesson, let’s answer these questions one by one.

Values in the country column

At the moment, there are ~250 countries in the world. Some of them have very long names like Saint Vincent and the Grenadines or South Georgia and the South Sandwich Islands (South Sandwich 🍔, really? 😄).

Quite often, organizations all over the world need to store country related information: customers address, delivery address, etc. It’s quite cumbersome to always refer to the country by its name (it literally cost paper or computer space). This is why the International Organization for Standardization (ISO) developed a standard – two-letter country codes to represent all countries. 💡

Country codes in the users table

When users sign up on the web or via a mobile app, their browser (or the mobile app) sends a request to the company’s servers with their email and password. But that’s not all of it! User’s cookies (for web signups) and an IP address are also visible to the server. ⚠

The country is derived from an IP address via the process called IP Geolocation. It’s very simple, actually – there’s literally a table of all IP addresses and their locations. There are companies like Maxmind which maintain these tables up to date and sell them as a service.

💡 To sum it up: every time someone signs up for Bindle we store not just their email and password, but also a country derived from the IP address.

Country codes

These are all country codes according to ISO 3166 standard:

Country code Country name
ad Andorra
ae United Arab Emirates
af Afghanistan
ag Antigua and Barbuda
ai Anguilla
al Albania
am Armenia
ao Angola
ap Asia/Pacific Region
aq Antarctica
ar Argentina
as American Samoa
at Austria
au Australia
aw Aruba
ax Aland Islands
az Azerbaijan
ba Bosnia and Herzegovina
bb Barbados
bd Bangladesh
be Belgium
bf Burkina Faso
bg Bulgaria
bh Bahrain
bi Burundi
bj Benin
bl Saint Barthelemy
bm Bermuda
bn Brunei Darussalam
bo Bolivia
bq Bonaire, Saint Eustatius and Saba
br Brazil
bs Bahamas
bt Bhutan
bv Bouvet Island
bw Botswana
by Belarus
bz Belize
ca Canada
cc Cocos (Keeling) Islands
cd Congo, The Democratic Republic of the
cf Central African Republic
cg Congo
ch Switzerland
ci Cote d’Ivoire
ck Cook Islands
cl Chile
cm Cameroon
cn China
co Colombia
cr Costa Rica
cu Cuba
cv Cape Verde
cw Curacao
cx Christmas Island
cy Cyprus
cz Czech Republic
de Germany
dj Djibouti
dk Denmark
dm Dominica
do Dominican Republic
dz Algeria
ec Ecuador
ee Estonia
eg Egypt
eh Western Sahara
er Eritrea
es Spain
et Ethiopia
eu Europe
fi Finland
fj Fiji
fk Falkland Islands (Malvinas)
fm Micronesia, Federated States of
fo Faroe Islands
fr France
ga Gabon
gb United Kingdom
gd Grenada
ge Georgia
gf French Guiana
gg Guernsey
gh Ghana
gi Gibraltar
gl Greenland
gm Gambia
gn Guinea
gp Guadeloupe
gq Equatorial Guinea
gr Greece
gs South Georgia and the South Sandwich Islands
gt Guatemala
gu Guam
gw Guinea-Bissau
gy Guyana
hk Hong Kong
hm Heard Island and McDonald Islands
hn Honduras
hr Croatia
ht Haiti
hu Hungary
id Indonesia
ie Ireland
il Israel
im Isle of Man
in India
io British Indian Ocean Territory
iq Iraq
ir Iran, Islamic Republic of
is Iceland
it Italy
je Jersey
jm Jamaica
jo Jordan
jp Japan
ke Kenya
kg Kyrgyzstan
kh Cambodia
ki Kiribati
km Comoros
kn Saint Kitts and Nevis
kp Korea, Democratic People’s Republic of
kr Korea, Republic of
kw Kuwait
ky Cayman Islands
kz Kazakhstan
la Lao People’s Democratic Republic
lb Lebanon
lc Saint Lucia
li Liechtenstein
lk Sri Lanka
lr Liberia
ls Lesotho
lt Lithuania
lu Luxembourg
lv Latvia
ly Libyan Arab Jamahiriya
ma Morocco
mc Monaco
md Moldova, Republic of
me Montenegro
mf Saint Martin
mg Madagascar
mh Marshall Islands
mk Macedonia
ml Mali
mm Myanmar
mn Mongolia
mo Macao
mp Northern Mariana Islands
mq Martinique
mr Mauritania
ms Montserrat
mt Malta
mu Mauritius
mv Maldives
mw Malawi
mx Mexico
my Malaysia
mz Mozambique
na Namibia
nc New Caledonia
ne Niger
nf Norfolk Island
ng Nigeria
ni Nicaragua
nl Netherlands
no Norway
np Nepal
nr Nauru
nu Niue
nz New Zealand
om Oman
pa Panama
pe Peru
pf French Polynesia
pg Papua New Guinea
ph Philippines
pk Pakistan
pl Poland
pm Saint Pierre and Miquelon
pn Pitcairn
pr Puerto Rico
ps Palestinian Territory
pt Portugal
pw Palau
py Paraguay
qa Qatar
re Reunion
ro Romania
rs Serbia
ru Russian Federation
rw Rwanda
sa Saudi Arabia
sb Solomon Islands
sc Seychelles
sd Sudan
se Sweden
sg Singapore
sh Saint Helena
si Slovenia
sj Svalbard and Jan Mayen
sk Slovakia
sl Sierra Leone
sm San Marino
sn Senegal
so Somalia
sr Suriname
ss South Sudan
st Sao Tome and Principe
sv El Salvador
sx Sint Maarten
sy Syrian Arab Republic
sz Swaziland
tc Turks and Caicos Islands
td Chad
tf French Southern Territories
tg Togo
th Thailand
tj Tajikistan
tk Tokelau
tl Timor-Leste
tm Turkmenistan
tn Tunisia
to Tonga
tr Turkey
tt Trinidad and Tobago
tv Tuvalu
tw Taiwan
tz Tanzania, United Republic of
ua Ukraine
ug Uganda
um United States Minor Outlying Islands
us United States
uy Uruguay
uz Uzbekistan
va Holy See (Vatican City State)
vc Saint Vincent and the Grenadines
ve Venezuela
vg Virgin Islands, British
vi Virgin Islands, U.S.
vn Vietnam
vu Vanuatu
wf Wallis and Futuna
ws Samoa
ye Yemen
yt Mayotte
za South Africa
zm Zambia
zw Zimbabwe

Whoa, a lot of country codes! 🙈 😄

We’ve touched enough on filters and even learned some tech specifics behind country codes. It’s time we do the first exercise! 🚀

Anatoli Makarevich, author of SQL Habit About SQL Habit

Hi, it’s Anatoli, the author of SQL Habit. 👋

SQL Habit is a course (or, as some of the students say, “business simulator”). It’s based on a story of a fictional startup called Bindle. You’ll play a role of their Data Analyst 📊 and solve real-life challenges from Business, Marketing, and Product Management.

SQL Habit course is made of bite-sized lessons (you’re looking at one atm) and exercises. They always have a real-life setting and detailed explanations. You can immediately apply everything you’ve learned at work. 🚀

“well worth the money”

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