instruction: how many patients received antiemetic - serotonin antagonist within 2 months after having received oxygen therapy (> 60%) - non-rebreather mask?
response: SELECT COUNT(DISTINCT t1.uniquepid) FROM (SELECT patient.uniquepid, treatment.treatmenttime FROM treatment JOIN patient ON treatment.patientunitstayid = patient.patientunitstayid WHERE treatment.treatmentname = 'oxygen therapy (> 60%) - non-rebreather mask') AS t1 JOIN (SELECT patient.uniquepid, treatment.treatmenttime FROM treatment JOIN patient ON treatment.patientunitstayid = patient.patientunitstayid WHERE treatment.treatmentname = 'antiemetic - serotonin antagonist') AS t2 WHERE t1.treatmenttime < t2.treatmenttime AND DATETIME(t2.treatmenttime) BETWEEN DATETIME(t1.treatmenttime) AND DATETIME(t1.treatmenttime, '+2 month')