Note that these answers are not unique. There are many alternatives.

1. SELECT * FROM cia

   name	region	area	population	gdp
   Afghanistan	Asia	647500	21251821	18100000000
   Albania	Ethnic Groups in Eastern Europe, Europe	28750	3413904	3800000000
   Algeria	Africa	2381740	28539321	97100000000
   ...

2. 1. Give the names and the GDP for the countries with populations of at least 200 million (200000000)

      SELECT name, gdp FROM cia
        WHERE population>200000000;

      name	gdp
      China	2978800000000
      India	1253900000000
      Indonesia	619400000000
      United States	6738400000000

   2. Give the names and the per capita GDP for the countries with populations of at least 200 million

      SELECT name, gdp/population FROM cia
        WHERE population>200000000;

      name	gdp / population
      China	2476
      India	1339
      Indonesia	3042
      United States	25542

   3. Show the names and populations in millions for the countries of 'South America'

      SELECT name,population/1000000 FROM cia
        WHERE region='South America';

      name	population / 1000000
      Argentina	34.2927
      Bolivia	7.8962
      Brazil	160.7375
      Chile	14.1612
      Colombia	36.2002
      Ecuador	10.891
      Falkland Islands (Islas Malvinas)	0.0023
      French Guiana	0.1453
      Guyana	0.7238
      Paraguay	5.3582
      Peru	24.0874
      Suriname	0.4295
      Uruguay	3.2227
      Venezuela	21.0048

   4. Show the populations of 'France', 'Germany', 'Italy'

      SELECT name,population FROM cia
        WHERE name in ('France', 'Germany', 'Italy');

      name	population
      France	58109160
      Germany	81337541
      Italy	58261971

   5. Which countries have names including the word 'United'?

      SELECT name FROM cia
        WHERE name LIKE 'United%';

      name
      United Arab Emirates
      United Kingdom
      United States

3. 1. Which countries have populations larger than 'United States'

      SELECT name FROM cia
        WHERE population >
          (SELECT population FROM cia WHERE name='United States');

      name
      China
      India

   2. List the countries of the regions containing 'Ukraine', 'Hungary'

      We note that the query

      SELECT region FROM cia
      WHERE name IN ('Ukraine', 'Hungary')

      returns a list of two regions:

      region
      Commonwealth of Independent States - European States
      Ethnic Groups in Eastern Europe, Europe

      This table result can be used with an IN clause:

      SELECT name FROM cia
        WHERE region IN
          (SELECT region FROM cia WHERE name IN ('Ukraine', 'Hungary'));

      name
      Albania
      Armenia
      Azerbaijan
      Belarus
      Bosnia and Herzegovina
      Bulgaria
      Croatia
      Czech Republic
      Hungary
      Macedonia, The Former Yugoslav Republic of
      Moldova
      Poland
      Romania
      Serbia and Montenegro
      Slovakia
      Slovenia
      Ukraine

   3. Show the European countries with a per capita GDP greater than 'United Kingdom'

      SELECT name FROM cia
      WHERE region = 'Europe' AND gdp/population >
        (SELECT gdp/population FROM cia WHERE name='United Kingdom');
      

      name
      Belgium
      Denmark
      France
      Liechtenstein
      Luxembourg
      Norway
      Sweden
      Switzerland

      Depressing isn't it, but where is Germany?

4.  

   1. Show the total population of the world.

      SELECT SUM(population) FROM cia;

      SUM OF population
      5729533973

      About 6 thousand million.

   2. List all the regions.

      SELECT DISTINCT region FROM cia;

      region
      Africa
      Antarctic Region
      Arctic Region
      Asia
      Central America and the Caribbean
      Commonwealth of Independent States - Central Asian States
      Commonwealth of Independent States - European States
      Ethnic Groups in Eastern Europe, Europe
      Europe
      Middle East
      North America
      Oceania
      South America
      Southeast Asia
      World

   3. List the countries which have a GDP greater than the whole of Africa

      SELECT name FROM cia
        WHERE gdp >
         (SELECT SUM(gdp) FROM cia WHERE region='Africa');

      name
      China
      Germany
      India
      Japan
      United States

5. 1. For each region show the number of countries of at least 10 million.

      SELECT region, COUNT(name) FROM cia
      WHERE population > 10000000
      GROUP BY region;

      region	COUNT OF name
      Africa	19
      Asia	11
      Central America and the Caribbean	2
      Commonwealth of Independent States - Central Asian States	2
      Commonwealth of Independent States - European States	2
      Ethnic Groups in Eastern Europe, Europe	5
      Europe	9
      Middle East	6
      North America	3
      Oceania	1
      South America	7
      Southeast Asia	8

   2. List the regions with total populations of at least 100 million.

      SELECT region, SUM(population) FROM cia
      GROUP BY region
      HAVING SUM(population)>100000000;

      Note SQL Executor does not support HAVING.

      region	SUM OF population
      Africa	715369983
      Asia	2809426876
      Ethnic Groups in Eastern Europe, Europe	123057096
      Europe	393708823
      Middle East	227395296
      North America	386302811
      South America	319152866
      Southeast Asia	522458680