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创建测试表,随便弄了点数据:
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create table test
(timestamp date);
insert into test values (to_date('2017-12-7 9:00:00','yyyy-mm-dd hh24:mi:ss'));
insert into test values (to_date('2017-12-7 9:01:00','yyyy-mm-dd hh24:mi:ss'));
insert into test values (to_date('2017-12-7 11:00:00','yyyy-mm-dd hh24:mi:ss'));
insert into test values (to_date('2017-12-7 11:20:00','yyyy-mm-dd hh24:mi:ss'));
insert into test values (to_date('2017-12-7 11:30:00','yyyy-mm-dd hh24:mi:ss'));
commit;
执行:
select to_char(timestamp,'yyyy-mm-dd hh24')||':00:00',count(*) from test group by to_char(timestamp,'yyyy-mm-dd hh24')||':00:00'
结果:
只针对时间字段为date类型有效,其他类型的话需要改语句。
select
decode(tl, '00:00——00:30', to_char(a-1,'yyyymmdd'), to_char(a,'yyyymmdd')) as 天,
decode(tl, '00:00——00:30', '16:31——00:30', '16:31——00:00', '16:31——00:30', t1) as 时间段,
sum(b)
from
(
select
a,
case
when to_char(a, 'hhmi') ='0030' then '00:00——00:30'
when to_char(a, 'hhmi') between '0031' and '0830' then '00:30——08:30'
when to_char(a, 'hhmi') between '0031' and '1630' then '00:31——16:30'
when to_char(a, 'hhmi') = '1631' then '16:31——00:00'
else ''
end as tl,
b
from table_name
)
group by
decode(tl, '00:00——00:30', to_char(a-1,'yyyymmdd'), to_char(a,'yyyymmdd')),
decode(tl, '00:00——00:30', '16:31——00:30', '16:31——00:00', '16:31——00:30', t1)
select time,count(time) from (
select substr('2014-01-01 20:03:00',1,13) as time from table_name) group by time;