Create big-countries.sql

kamyu104 · web-flow · commit f2d71530bd43 · 2017-10-06T22:55:16.000+08:00
diff --git a/MySQL/big-countries.sql b/MySQL/big-countries.sql
@@ -0,0 +1,27 @@
+# Time:  O(n)
+# Space: O(1)
+
+# There is a table World
+# +-----------------+------------+------------+--------------+---------------+
+# | name            | continent  | area       | population   | gdp           |
+# +-----------------+------------+------------+--------------+---------------+
+# | Afghanistan     | Asia       | 652230     | 25500100     | 20343000      |
+# | Albania         | Europe     | 28748      | 2831741      | 12960000      |
+# | Algeria         | Africa     | 2381741    | 37100000     | 188681000     |
+# | Andorra         | Europe     | 468        | 78115        | 3712000       |
+# | Angola          | Africa     | 1246700    | 20609294     | 100990000     |
+# +-----------------+------------+------------+--------------+---------------+
+#
+# A country is big if it has an area of bigger than 3 million square km or a population of more than 25 million.
+# Write a SQL solution to output big countries' name, population and area.
+# For example, according to the above table, we should output:
+# +--------------+-------------+--------------+
+# | name         | population  | area         |
+# +--------------+-------------+--------------+
+# | Afghanistan  | 25500100    | 652230       |
+# | Algeria      | 37100000    | 2381741      |
+# +--------------+-------------+--------------+
+
+SELECT name, population, area
+FROM World
+WHERE area > 3000000 OR population > 25000000;
