# 7) Using regex to select city starts with all letters and ends with vowels
SELECT COUNT(city) - COUNT(DISTINCT city)
	FROM citytable WHERE city RLIKE '^[nz].*[^aiueo]$'
		AND lat > 121.5 AND lon < 25.3;

# 8) Update lat to p*lat, lon to q*lon using parity checking
UPDATE citytable
	SET lat = lat*2, lon = lon*5
	WHERE CASE
		WHEN 'od' = 'ev' THEN (id % 2) = 0
		ELSE id % 2 = 1 END;
        
# 9) Find sum of lat, lon, and difference between biggest and smallest city
SELECT ROUND(SUM(lat), 3), ROUND(SUM(lon), 3), MAX(LENGTH(city)) - MIN(LENGTH(city))
	FROM (SELECT*FROM citytable
			WHERE CASE
				WHEN 'even' = 'even' THEN (id % 2) = 0
				ELSE id % 2 = 1 END
			ORDER BY LENGTH(city) DESC, city DESC LIMIT 5) AS newTable;