3. Solution of Hacker Rank Weather Observation Station 4.

Author: neptune | 23rd-Jan-2023
🏷️ #SQL #Hackerrank

Weather Observation Station 4

Problem Statement : Find the difference between the total number of CITY entries in the table and the number of distinct CITY entries in the table.

The STATION table is described as follows:

where LAT_N is the northern latitude and LONG_W is the western longitude.

For example, if there are three records in the table with CITY values 'New York', 'New York', 'Bengalaru', there are 2 different city names: 'New York' and 'Bengalaru'.

Answer will be (Total cities) - (Unique cities)=3-2=1






Solution :

For this challenge, we must:

  1. Use a Count() aggregate function to count the cities.

  2. Use a Count() again to find Distinct cities then subtract.


Query :


SELECT Count(CITY) - Count(Distinct (CITY)) 

FROM STATION;


Output:



Hope you understand !!!

If you have any questions let me know in the comment section.