where left(happendate,7) = '${t1}' 这是等于参数的当月,我想等于参数t1的上一个月
where left(happendate,7) = '${FORMAT(MONTHDELTA(t1,-1),"yyyy-MM")}'
where left(happendate,7) = '${FORMAT(MONTHDELTA(t1,-1),""yyyy-MM)}'
left(date_add(happendate,interval 1 month),7) = '${t1}'