instruction: show us the top four most common diagnoses during this year?
response: SELECT t1.diagnosisname FROM (SELECT diagnosis.diagnosisname, DENSE_RANK() OVER (ORDER BY COUNT(*) DESC) AS c1 FROM diagnosis WHERE DATETIME(diagnosis.diagnosistime, 'start of year') = DATETIME(CURRENT_TIME(), 'start of year', '-0 year') GROUP BY diagnosis.diagnosisname) AS t1 WHERE t1.c1 <= 4