日期:2014-05-18  浏览次数:20335 次

使用存储过程比较值
有一个数据库表Test:
name types state times
A AA 1 2011-12-30 09:35:54
A AA 1 2011-12-30 09:35:54
A AA 1 2011-12-30 09:35:54
A BB 1 2011-12-30 09:35:54
A BB 1 2011-12-30 09:35:54
A BB 1 2011-12-30 09:35:54
A AA 1 2011-12-30 09:45:54
A AA 1 2011-12-30 09:45:54
A AA 1 2011-12-30 09:45:54
A BB 1 2011-12-30 09:45:54
A BB 1 2011-12-30 09:45:54
A BB 1 2011-12-30 09:45:54
A BB 1 2011-12-30 11:45:54
A AA 1 2011-12-30 11:45:54
A AA 2 2011-12-30 11:45:54
A AA 1 2011-12-30 11:45:54
A BB 1 2011-12-30 11:45:54
A BB 2 2011-12-30 11:45:54
A BB 1 2011-12-30 11:45:54
A BB 2 2011-12-30 11:45:54
要求:查询当前最大时间的数据和两小时前的最大时间的数据相比较,如果两小时前的state为1,而现在state为2,则显示现在最大时间时的值,上面的数据通过查询应显示成如下结果:

name types state times
A AA 2 2011-12-30 11:45:54
A BB 2 2011-12-30 11:45:54
A BB 2 2011-12-30 11:45:54
 


------解决方案--------------------
SQL code

create proc getMaxTime
(
   @hour int  --时间间隔(单位:小时)
)
as
begin
 declare @time1 datetime
 declare @time2 datetime
 declare @state1 int
 declare @state2 int
--查询当前最大时间记录
 select 
 @time1=max(times),
 @state1=state
 from test
 group by name
--查询hour小时前最大时间记录
 select 
 @time2=max(times),
 @state2=state
 from test
 where datediff(hh,times,getdate())>@hour
 group by name
 
 if(@time1 is not null and @time2 is not null)
 begin
   if(@state1==2 and @state2==1)
   begin
     return @time1
   end
   else
   begin
     return @time2
   end
   --相应的其他判断并返回数据
 end
end

------解决方案--------------------
SQL code
--> 测试数据:#
if object_id('tempdb.dbo.#') is not null drop table #
create table #(name varchar(8), types varchar(8), state int, times datetime)
insert into #
select 'A', 'AA', 1, '2011-12-30 09:35:54' union all
select 'A', 'AA', 1, '2011-12-30 09:35:54' union all
select 'A', 'AA', 1, '2011-12-30 09:35:54' union all
select 'A', 'BB', 1, '2011-12-30 09:35:54' union all
select 'A', 'BB', 1, '2011-12-30 09:35:54' union all
select 'A', 'BB', 1, '2011-12-30 09:35:54' union all
select 'A', 'AA', 1, '2011-12-30 09:45:54' union all
select 'A', 'AA', 1, '2011-12-30 09:45:54' union all
select 'A', 'AA', 1, '2011-12-30 09:45:54' union all
select 'A', 'BB', 1, '2011-12-30 09:45:54' union all
select 'A', 'BB', 1, '2011-12-30 09:45:54' union all
select 'A', 'BB', 1, '2011-12-30 09:45:54' union all
select 'A', 'BB', 1, '2011-12-30 11:45:54' union all
select 'A', 'AA', 1, '2011-12-30 11:45:54' union all
select 'A', 'AA', 2, '2011-12-30 11:45:54' union all
select 'A', 'AA', 1, '2011-12-30 11:45:54' union all
select 'A', 'BB', 1, '2011-12-30 11:45:54' union all
select 'A', 'BB', 2, '2011-12-30 11:45:54' union all
select 'A', 'BB', 1, '2011-12-30 11:45:54' union all
select 'A', 'BB', 2, '2011-12-30 11:45:54'

select * from # t where state=2 and exists (select 1 from # where types=t.types and state=1 and datediff(hour,times,t.times)=2)

/*
name types state times
A AA 2 2011-12-30 11:45:54
A BB 2 2011-12-30 11:45:54
A BB 2 2011-12-30 11:45:54
*/