해당월의 첫날 : 2019-07-01
select biz_cdts , count(*) from member_base
where TRUNC(join_dtm, ‘MM’) = ‘2019-07-01’
group by biz_cdts
select biz_cdts , count(*) from member_base
where TRUNC(join_dtm, ‘MM’) = TRUNC( trunc(to_date(‘2019-07-01′,’RRRR-MM-DD’),’MM’) -1 , ‘MM’)
group by biz_cdts