calculate how many times patient 19627 received a laboratory test for potassium until 01/2103.
select count(*) from labevents where labevents.itemid in ( select d_labitems.itemid from d_labitems where d_labitems.label = 'potassium' ) and labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 19627 ) and strftime('%y-%m',labevents.charttime) <= '2103-01'