count the number of patients who until 2104 were diagnosed with oliguria & anuria.
select count( distinct admissions.subject_id ) from admissions where admissions.hadm_id in ( select diagnoses_icd.hadm_id from diagnoses_icd where diagnoses_icd.icd9_code = ( select d_icd_diagnoses.icd9_code from d_icd_diagnoses where d_icd_diagnoses.short_title = 'oliguria & anuria' ) and strftime('%y',diagnoses_icd.charttime) <= '2104' )