sql多表联查实例

sql多表联查实例下面提供四款sql多表关联查询的实例，个个效率不一样。

sql多表联查实例
下面提供四款sql多表关联查询的实例，个个效率不一样。
select * from order_info as a ,ivrlog4ivrdlvinst as b
where
(a.saleorder=b.ext1_skill and b.start_date=@date1 and se_id='55' and b.ext1_skill!='')
and convert(varchar(10),a.instime,112)=@date2 and max(a.instime)

方法二

select * from order_info as a
where a.saleorder=(
    select b.ext1_skill from ivrlog4ivrdlvinst as b
    where b.start_date=@date1 and se_id='55'
    and b.ext1_skill!='')
and convert(varchar(10),max(a.instime),112)=@date2

方法三

declare
@date1 varchar(20),
@date2 varchar(20)    
set @date1='20100812'
set @date2='2010-08-12'

select * from order_info as a
where a.saleorder=
(select b.ext1_skill from ivrlog4ivrdlvinst as b where b.start_date=@date1 and se_id='55' and b.ext1_skill!='')
and convert(varchar(10),a.instime,112)=@date2
and max(a.instime)

方法四

select b.caller, b.start_date, b.start_time, b.ext1_skill,
       c.deliveryno, c.destroyresult, c.deliverydate, c.deliverytime, c.arrangetime, c.driverphone, c.drivermobile,
       a.servicedate, a.servicetime, a.workertel
 from order_info as a ,ivrlog4ivrdlvinst as b ,delivery_info as c
 where
  a.saleorder in (select b.ext1_skill from ivrlog4ivrdlvinst where b.start_date=@date1 and b.se_id='55' and b.ext1_skill!='')
  and convert(varchar(10),a.instime,112)=@date2
 order by b.start_date desc, b.start_time desc