Justus-coded

/*
Query the list of CITY names from STATION that do not start with vowels. Your result cannot contain duplicates.
*/

SELECT DISTINCT CITY 
FROM STATION
WHERE LEFT(UPPER(CITY), 1) NOT IN ('A', 'E', 'I', 'O', 'U')

Justus-coded

/*
Query the list of CITY names from STATION which have vowels (i.e., a, e, i, o, and u) as both their first and last characters. Your result cannot contain duplicates.
*/
SELECT DISTINCT CITY
FROM STATION
WHERE (LEFT(UPPER(CITY),1) IN ('A','E','I','O','U')) AND (RIGHT(UPPER(CITY),1) IN ('A','E','I','O','U'))

Justus-coded

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

SELECT DISTINCT CITY
FROM STATION
WHERE RIGHT(UPPER(CITY),1) IN ('A', 'E', 'I', 'O', 'U')