HackerRank - Weather Observation Station 6

April - 25/2025

Problem:

Query the list of CITY names starting with vowels (i.e., a, e, i, o, or u) from STATION. Your result cannot contain duplicates.

Field Type
ID NUMBER
CITY VARCHAR2(21)
STATE VARCHAR2(2)
LAT_N NUMBER
LAT_W NUMBER

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

# Solution

            
    SELECT DISTINCT CITY
    FROM STATION
    WHERE CITY LIKE 'A%' OR
          CITY LIKE 'E%' OR
          CITY LIKE 'I%' OR
          CITY LIKE 'O%' OR
          CITY LIKE 'U%';

# Solution_01

              
    SELECT DISTINCT CITY
    FROM STATION
    WHERE SUBSTR(CITY, 1, 1) IN ('A', 'E', 'I', 'O', 'U') ORDER BY 1;

# Solution_02

              
    SELECT DISTINCT CITY
    FROM STATION
    WHERE SUBSTR(LOWER(CITY), 1, 1) IN ('a', 'e', 'i', 'o', 'u') ORDER BY CITY ASC;

# Note:

            
    Substring

    'London'
    'Paris'

    SUBSTR('London', 1, 1) = 'L'
    SUBSTR('Paris', 1, 1) = 'P'

    #!---------------------!#

    Lower

    'Tokyo'
    'New York'

    LOWER('Tokyo') = 'tokyo'
    LOWER('New York') = 'new york'

    #!---------------------!#

    ORDER BY ASC

    'Athens'
    'Orlando'
    'Edmonton'
    'Irvine'

    'Athens'
    'Edmonton'
    'Irvine'
    'Orlando'

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