[HackerRank](E) Weather Observation Station 4

https://www.hackerrank.com/challenges/weather-observation-station-4/problem?isFullScreen=true 

Weather Observation Station 4 | HackerRank

 

[문제]

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'. The query returns  1,

because total number of records - number of unique city names = 3 - 2 = 1

 

 

[답]

- oracle

select count(city)-count(distinct(city)) from station;

 

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