instruction: what were the four most commonly performed lab tests for patients who had previously been diagnosed with fracture of skull - base in the same hospital visit, last year?
response: SELECT t3.labname FROM (SELECT t2.labname, DENSE_RANK() OVER (ORDER BY COUNT(*) DESC) AS c1 FROM (SELECT patient.uniquepid, diagnosis.diagnosistime, patient.patienthealthsystemstayid FROM diagnosis JOIN patient ON diagnosis.patientunitstayid = patient.patientunitstayid WHERE diagnosis.diagnosisname = 'fracture of skull - base' AND DATETIME(diagnosis.diagnosistime, 'start of year') = DATETIME(CURRENT_TIME(), 'start of year', '-1 year')) AS t1 JOIN (SELECT patient.uniquepid, lab.labname, lab.labresulttime, patient.patienthealthsystemstayid FROM lab JOIN patient ON lab.patientunitstayid = patient.patientunitstayid WHERE DATETIME(lab.labresulttime, 'start of year') = DATETIME(CURRENT_TIME(), 'start of year', '-1 year')) AS t2 ON t1.uniquepid = t2.uniquepid WHERE t1.diagnosistime < t2.labresulttime AND t1.patienthealthsystemstayid = t2.patienthealthsystemstayid GROUP BY t2.labname) AS t3 WHERE t3.c1 <= 4