Solutions to SQL problems on hackerrank.

Domain	Category	Problem	Solution in Oracle	Solution in Mysql
Select	Easy	Select All	select * from city;	select * from city;
		Select by ID	select * from city      where id=1661;	select * from city where id=1661;
		Japanese Cities’ Detail	select * from city where countrycode=’JPN’;	select * from city where countrycode=’JPN’;
		Japanese Cities’ Name	select Name from city where countrycode=’JPN’;	select Name from city where countrycode=’JPN’;
		Weather Observation Station 1	select city, state from station order by city, state asc;	select city, state from station order by city, state asc;
		Weather Observation Station 3	select distinct city from station where mod(id,2)=0 order by city asc;	select distinct city from station where id % 2 = 0 order by city asc;
		Weather Observation Station 4	select count(*) – count(distinct city) from station;	select count(*) – count(distinct city) from station;
		Weather Observation Station 6	select distinct city from station where regexp_like  (city,’^[aeiouAEIOU]’) order by city asc;	select distinct city from station where city regexp ‘^[aeiouAEIOU]’ order by city asc;
		Weather Observation Station 7	select distinct city from station where regexp_like (city,'[aeiouAEIOU]$’) order by city asc;	select distinct city from station where city regexp ‘[aeiouAEIOU]$’ order by city asc;
		Weather Observation Station 8	select distinct city from station where regexp_like (city,’^[aeiouAEIOU].*[aeiouAEIOU]$’) order by city asc;	select distinct city from station where city regexp ‘^[aeiouAEIOU].*[aeiouAEIOU]$’ order by city asc;
		Weather Observation Station 9	select distinct city from station where not regexp_like (city, ‘^[aeiouAEIOU]’) order by city asc;	select distinct city from station where city not regexp ‘^[aeiouAEIOU]’ order by city asc;
		Weather Observation Station 10	select distinct city from station where not regexp_like(city, ‘[aeiouAEIOU]$’) order by city asc;	select distinct city from station where city not regexp ‘[aeiouAEIOU]$’ order by city asc;
		Weather Observation Station 11	select distinct city from station where not regexp_like(city, ‘^[aeiouAEIOU].*[aeiouAEIOU]$’) order by city asc;	select distinct city from station where city not regexp ‘^[aeiouAEIOU].*[aeiouAEIOU]$’ order by city asc;
		Weather Observation Station 12	select distinct city from station where not regexp_like(city, ‘^[aeiouAEIOU]’) and not regexp_like(city, ‘[aeiouAEIOU]$’) order by city asc;	select distinct city from station where city not regexp ‘^[aeiouAEIOU]’ and city not regexp ‘[aeiouAEIOU]$’ order by city asc;
	Medium	Weather Observation Station 5	select * from (select city,length(city) FROM STATION order by length(city) asc,city asc) where ROWNUM=1; select * from (select city,length(city) FROM STATION order by length(city) desc,city asc) where ROWNUM=1;	select city,length(city) FROM STATION order by length(city) asc,city asc LIMIT 1; select  city,length(city) FROM STATION order by length(city) desc,city asc LIMIT 1;