In this blog I would like to give a detail breakdown how I solved the Weather Observation Station 13 Challenge in Hacker Rank using Oracle SQL.
In the challenge, it is requested that you write a query that returns the sum of Northern Latitudes (LAT_N) from a table called** Station** where the values are greater than 38.7880 and less than 137.2345. The value must be truncated to 4 decimal places.
I reviewed the instructions one more time to make sure I captured the key words of what was being asked.
I ran *Select ** to see what the data looked like. I then added to the query where I only return results between 38.7880 and 137.2345;
Select * From Station;
Not only does between return all values between the two given but it also returns 38.7880 and 137.2345.
Select lat_n From Station Where lat_n between 38.7880 and 137.2345;
Next, I used an analytic function Sum to sum all the lat_n returned by my query.
Select sum(lat_n) sum_lat_n From Station where lat_n between 38.7880 and 137.2345;
This returns 36354.8135. Our answer, but there is one last thing it asked for us to do. We need to truncate sum to the nearest 4 decimals.
select trunc(sum(lat_n),4) sum_lat_n from station where lat_n between 38.7880 and 137.2345;
There is our answer!
