HackerRank: [SQL Basic Select] (12/20) Weather Observation Station-7 | regexp_like, like, right function in SQL

I started studying SQL from a very famous site - HackerRank. Here I will try to provide multiple approaches & solutions to the same problem. It will help you learn and understand SQL in a better way.

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SQL Problem Statement:

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

The STATION table is described as follows:

Table: STATION

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

Sample data in Table (STATION):

ID CITY STATE LAT_N LONG_W
794 Kissee Mills MO 140 73
824 Loma Mar CA 49 131
603 Sandy Hook CT 72 148
478 Tipton IN 34 98
619 Arlington CO 75 93
711 Turner AR 50 101
839 Slidell LA 85 152
.
.
.
754 South Haven MI 145 53
144 Eskridge KS 1

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Solution-1: Using LIKE Function (MySQL Query):

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';

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Solution-2: Using REGEXP_LIKE Function (MySQL Query):

SELECT DISTINCT CITY
FROM STATION
WHERE REGEXP_LIKE(CITY, '[aeiou]$', 'i');

NOTE: 

1. "$" character in REGEXP_LIKE function is used to check string ending with matching pattern.
2. "[]" (square brackets) are used to pass the list of characters to check. Here, it is a,e,i,o,u.
3. "i" is passed as an argument to the REGEXP_LIKE function for case_insensitivity. i.e. It will try check match with small as well as capital letters.

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Solution-3: Using RIGHT Function (MySQL Query):

SELECT DISTINCT CITY
FROM STATION
WHERE RIGHT(CITY,1) in ('a','e','i','o','u','A','E','I','O','U');

NOTE: 

1. The RIGHT function is used to take a substring of CITY starting from the right, and "1" is passed as an argument to select only 1 character from the right. 

Sample Output:

Glencoe
Chelsea
Pelahatchie
Dorrance
Cahone
Upperco
Waipahu
Millville
Aguanga
Morenci
South El Monte
Gustine
Delano

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-Akshay P Daga