Aggregation

Revising Aggregations - The Count Function

Revising Aggregations - The Count Function | HackerRankHackerRank

select count(*) from CITY
where POPULATION > 100000;

Revising Aggregations - The Sum Function

Revising Aggregations - The Sum Function | HackerRankHackerRank

select sum(POPULATION) from CITY
where DISTRICT = 'California';

Revising Aggregations - Averages

Revising Aggregations - Averages | HackerRankHackerRank

select avg(POPULATION) from CITY
where DISTRICT = 'California';

Average Population

Average Population | HackerRankHackerRank

select round(avg(POPULATION)) from CITY;

Japan Population

Japan Population | HackerRankHackerRank

select sum(POPULATION) from CITY
where COUNTRYCODE = 'JPN';

Population Density Difference

Population Density Difference | HackerRankHackerRank

select max(POPULATION) - min(POPULATION) from CITY;

The Blunder

The Blunder | HackerRankHackerRank

select ceil(avg(Salary) - avg(replace(Salary, '0', ''))) from EMPLOYEES;

Top Earners

Top Earners | HackerRankHackerRank

select * from (
    select salary * months, count(*) from Employee
    group by salary * months
    order by 1 desc)
where rownum = 1;

Weather Observation Station 2

Weather Observation Station 2 | HackerRankHackerRank

select round(sum(LAT_N),2), round(sum(LONG_W),2) from STATION;

Weather Observation Station 13

Weather Observation Station 13 | HackerRankHackerRank

select round(sum(LAT_N), 4) from STATION
where LAT_N > 38.7880 and LAT_N < 137.2345;

Weather Observation Station 14

Weather Observation Station 14 | HackerRankHackerRank

select trunc(max(LAT_N),4) from STATION
where LAT_N < 137.2345;

Weather Observation Station 15

Weather Observation Station 15 | HackerRankHackerRank

select round(LONG_W,4) from STATION
where LAT_N = (select max(LAT_N) from STATION where LAT_N < 137.2345);

Weather Observation Station 16

Weather Observation Station 16 | HackerRankHackerRank

select round(min(LAT_N),4) from STATION
where LAT_N > 38.7780;

Weather Observation Station 17

Weather Observation Station 17 | HackerRankHackerRank

select * from (
    select round(LONG_W, 4) from STATION
    where LAT_N > 38.7780
    order by LAT_N asc)
where rownum = 1;

Weather Observation Station 18

Weather Observation Station 18 | HackerRankHackerRank

select round(((max(LAT_N) - min(LAT_N)) + (max(LONG_W) - min(LONG_W))),4) 
from STATION;

Weather Observation Station 19

Weather Observation Station 19 | HackerRankHackerRank

select round(sqrt(
        power((max(LAT_N) - min(LAT_N)),2) + 
        power((max(LONG_W) - min(LONG_W)),2)
),4)
from STATION;

Weather Observation Station 20

Weather Observation Station 20 | HackerRankHackerRank

select round(median(LAT_N),4) from STATION;