instruction: what was the first value of rdw of patient 15905 since 110 months ago?
response: SELECT labevents.valuenum FROM labevents WHERE labevents.hadm_id IN (SELECT admissions.hadm_id FROM admissions WHERE admissions.subject_id = 15905) AND labevents.itemid IN (SELECT d_labitems.itemid FROM d_labitems WHERE d_labitems.label = 'rdw') AND DATETIME(labevents.charttime) >= DATETIME(CURRENT_TIME(), '-110 month') ORDER BY labevents.charttime LIMIT 1