CREATE TABLE [dbo].[PRE_Follow](
    [ID] [int] IDENTITY(1,1) NOT NULL,
    [UserNumber] [varchar](50) NOT NULL,
    [FollowState] [int] NOT NULL CONSTRAINT [DF_EZX_Follow_FollowState]  DEFAULT ((0)),
    [FollowUserName] [nvarchar](500) NOT NULL,
    [FollowContent] [ntext] NULL,
    [FollowTime] [smalldatetime] NULL,
    [AddTime] [smalldatetime] NOT NULL CONSTRAINT [DF_EZX_Follow_AddTime]  DEFAULT (getdate()),
 CONSTRAINT [PK_PRE_Follow] PRIMARY KEY CLUSTERED 
(
    [ID] ASC,
    [UserNumber] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]

GO

Select tmp.UserNumber From PRE_Follow Inner Join(Select UserNumber,Max(FollowTime) as TopFollowTime From PRE_Follow Where FollowState=1 Group By UserNumber)as tmp on PRE_Follow.UserNumber=tmp.UserNumber And PRE_Follow.FollowTime=tmp.TopFollowTime And FollowTime<=Convert(DateTime,GetDate())

select *
from tb t
where not exists (select 1 from tb where 用户号=t.用户号 and followtime>t.followtime)
    and datediff(dd,getdate(),followtime)<0

------解决方案--------------------
SQL code
select * from tb t
where not exists (select 1 from tb where 用户号=t.用户号 and followtime>t.followtime and datediff(dd,getdate(),followtime)<0)
and datediff(dd,getdate(),t.followtime)<0

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

select t.ID 
from 
(select ID,
max(FollowTime) maxFollowTime 
from PRE_Follow group by ID) t
where datediff(d,t.maxFollowTime getdate())>=1

------解决方案--------------------
个人觉得你自己的语句
应该还行
主要看有没有走索引


------解决方案--------------------
探讨


个人觉得你自己的语句
应该还行
主要看有没有走索引


------解决方案--------------------
没什么好优化的。

------解决方案--------------------
这要根据你表数据的大小和分布情况

那个表数据特别多  
  PRE_Follow的UserNumber 可以索引一下

------解决方案--------------------
SQL code
--try
create index idx_usnum_ft
on [dbo].[PRE_Follow](UserNumber,FollowTime)