我有这个表：
[SDate - DateTime] [Value] - Represents a boolean
2010-11-16 10:10:00 1
2010-11-16 10:11:00 0
2010-11-16 10:12:00 1
2010-11-16 10:13:00 1
例如：
2010-11-16 10:10:00 0
2010-11-16 10:11:00 1
2010-11-16 10:12:00 0
2010-11-16 10:13:00 0
2010-11-16 10:14:00 1
2010-11-16 10:15:00 0
2010-11-16 10:16:00 1
...
5 changes
2010-11-16 10:10:00 0
2010-11-16 10:11:00 0
2010-11-16 10:12:00 0
2010-11-16 10:13:00 1
2010-11-16 10:14:00 1
2010-11-16 10:15:00 1
2010-11-16 10:16:00 1
...
1 change
解决方法
你可以用lag()：
select count(*)
from (select t.*,lag(value) order by (sdate) as prev_value
from table t
) t
where prev_value <> value ;
