instruction: count the numbers of patients who were prescribed hydromorphone 1 mg/1 ml syr within 2 months after having been diagnosed with chronic kidney disease - stage 3 (gfr 30-59) since 1 year ago.
response: SELECT COUNT(DISTINCT t1.uniquepid) FROM (SELECT patient.uniquepid, diagnosis.diagnosistime FROM diagnosis JOIN patient ON diagnosis.patientunitstayid = patient.patientunitstayid WHERE diagnosis.diagnosisname = 'chronic kidney disease - stage 3 (gfr 30-59)' AND DATETIME(diagnosis.diagnosistime) >= DATETIME(CURRENT_TIME(), '-1 year')) AS t1 JOIN (SELECT patient.uniquepid, medication.drugstarttime FROM medication JOIN patient ON medication.patientunitstayid = patient.patientunitstayid WHERE medication.drugname = 'hydromorphone 1 mg/1 ml syr' AND DATETIME(medication.drugstarttime) >= DATETIME(CURRENT_TIME(), '-1 year')) AS t2 WHERE t1.diagnosistime < t2.drugstarttime AND DATETIME(t2.drugstarttime) BETWEEN DATETIME(t1.diagnosistime) AND DATETIME(t1.diagnosistime, '+2 month')