The challenge involves the table
Each row of this table provides information about a country, including its continent, area, population, and GDP. We define a country as "big" if it has an area of at least 3 million km2 or a population of at least 25 million.
The task is to write an SQL query that reports the name, population, and area of the "big" countries.
Here's an example for better understanding:
Afghanistan and Algeria are considered "big" countries as their population or area exceeds the defined thresholds.
Let's explore two SQL solutions to this problem, examining their differences, strengths, and weaknesses.
The first solution retrieves countries from the table where the area is at least 3 million or the population is at least 25 million.
SELECT name, population, area FROM World WHERE area >= 3000000 OR population >= 25000000
This query achieves a runtime of 904ms, outperforming 92.98% of other submissions.
The second solution is very similar to the first, but it first checks for the population condition before the area condition.
SELECT name, population, area FROM World WHERE population >= 25000000 OR area >= 3000000
This query has a runtime of 983ms, beating 78.89% of other submissions.
Both solutions yield the same output but have minor performance differences due to the order of conditions in the WHERE clause. Thus, the ranking of solutions based on overall performance, from best to worst, is: Source Code 1 > Source Code 2.
You should choose the solution that best fits your specific performance requirements and expectations.
You can find the original problem at LeetCode.
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