select count(1), trunc(a.refund_insert_time, ‘hh24‘)
+ case when to_char(refund_insert_time,‘mi‘) >= ‘30‘ then numtodsinterval(30,‘minute‘) else numtodsinterval(0,‘minute‘) end
from refund_record a
where a.refund_complete_time < sysdate - 1
group by trunc(a.refund_insert_time, ‘hh24‘)
+ case when to_char(refund_insert_time,‘mi‘) >= ‘30‘ then numtodsinterval(30,‘minute‘) else numtodsinterval(0,‘minute‘) end;

 mysql

半小时分组统计个数sql