Problem

Table: World

+-------------+---------+
| Column Name | Type    |
+-------------+---------+
| name        | varchar |
| continent   | varchar |
| area        | int     |
| population  | int     |
| gdp         | int     |
+-------------+---------+

name is the primary key column for this table.
Each row of this table gives information about the name of a country, the continent to which it belongs, its area, the population, and its GDP value.

A country is big if:

  • it has an area of at least three million (i.e., 3000000 km^2), or
  • it has a population of at least twenty-five million (i.e., 25000000).

Write an SQL query to report the name, population, and area of the big countries.

Return the result table in any order.

The query result format is in the following example.

Examples

Example 1:

Input: World table:

+-------------+-----------+---------+------------+--------------+
| name        | continent | area    | population | gdp          |
+-------------+-----------+---------+------------+--------------+
| Afghanistan | Asia      | 652230  | 25500100   | 20343000000  |
| Albania     | Europe    | 28748   | 2831741    | 12960000000  |
| Algeria     | Africa    | 2381741 | 37100000   | 188681000000 |
| Andorra     | Europe    | 468     | 78115      | 3712000000   |
| Angola      | Africa    | 1246700 | 20609294   | 100990000000 |
+-------------+-----------+---------+------------+--------------+

Output:

+-------------+------------+---------+
| name        | population | area    |
+-------------+------------+---------+
| Afghanistan | 25500100   | 652230  |
| Algeria     | 37100000   | 2381741 |
+-------------+------------+---------+

Solution

Method 1 - Filter out with where

SQL
SELECT name, population, area
FROM World
WHERE area >= 3000000 OR population >= 25000000;
Pandas
import pandas as pd

def big_countries(world: pd.DataFrame) -> pd.DataFrame:
    big_countries_df = world[(world['area'] >= 3000000) | (world['population'] >= 25000000)]
    return big_countries_df[['name', 'population', 'area']]