SQL常用语句

发现好记性不如烂笔头这句话是真理已经很久了，呵呵，得真理用于实践了。

1、常用的Update语句：

update temp_id set temp_id.tier_id =lp_account.tier_id 
from temp_id, lp_account   
where temp_id.aid=lp_account.aid 
或者 
update a set tier_id  = l.tier_id 
from a inner join l on a.id = l.tid 

2、常用的Delete语句：

delete from t1 from t1 
inner join t2 
on t1.id = t2.tid 

3、常用的case,count查询语句：

select fr.departure_airport,fr.arrive_airport, 
count(case when fr.cumulate_cabin in ('F','A') then 1 else NULL end) as FACount, 
count(case when fr.cumulate_cabin in ('C','D') then 1 else NULL end) CDCount, 
count(case when fr.cumulate_cabin='W' then 1 else NULL end) WCount 
from fr_ffp_travel_detail fr 
where fr.flight_date>='2010-01-01' 
and fr.flight_date<='2010-12-01' 
and ((fr.departure_airport='CAN' and fr.arrive_airport='SYD') 
or (fr.departure_airport='CAN' and fr.arrive_airport='MEL') 
or (fr.departure_airport='CAN' and fr.arrive_airport='BNE') 
or (fr.departure_airport='CAN' and fr.arrive_airport='PEK') 
or (fr.departure_airport='PEK' and fr.arrive_airport='AMS') 
or (fr.departure_airport='CAN' and fr.arrive_airport='CDG') 
or (fr.departure_airport='CAN' and fr.arrive_airport='DXB') 
or (fr.departure_airport='CAN' and fr.arrive_airport='LAX') 
or (fr.departure_airport='DXB' and fr.arrive_airport='JED')) 
and fr.cumulate_cabin in 
('F','A','C','D','W') 
and fr.status='IN' 
and fr.airline_company='CZ' 
group by fr.departure_airport,fr.arrive_airport 

4、经典的左链接查询：
查出a中b不存在bid的记录：

select * from a 
left join b on a.aid = b.bid 
where b.name is null 

在连接的时候加上条件,即先过滤，再连接：

select branch_code, isnull(r.result,'NO'),count(c.sid) as allCount  
from cb_service_order c 
inner join fr_soc_flight f 
on c.departure_airport=f.departure_airport 
and c.flight_date=f.flight_date 
and c.flight_no=f.flight_no 
inner  join cb_service_response r 
on c.sid=r.sid 
and r.result_type='001' 
where c.sid is not null 
and c.flight_date>=:beginDate 
and c.flight_date<=:endDate 
and c.departure_airport in ('SHE','PEK','KWL','NNG','DLC','CAN','KWE','HAK','SYX','CGO','WUH','HRB','CSX','CGQ','SWA','PVG','SHA','URC','SZX','ZUH','CKG') 
and c.type=:type 
and c.cabin in ('F','A','P','J','C','D','I','W','Z','Y','T','K','H','M','B','E','G','L','N','O','Q','R','S','U','V','X') 
group by branch_code, isnull(r.result,'NO') 
order by branch_code 

5、去除重复记录的SQL

select * from gczbxx_zhao 
where viewid in ( select max(viewid) from gczbxx_zhao group by 
gcmc ) order by gkrq desc ---还是这个可行。 
或者： 
SELECT * 
FROM TB A INNER JOIN 
( 
   SELECT MIN(ID),NAME FROM TB WHERE TYPE = 1 AND CHECK = 0 GROUP BY NAME 
) B ON A.ID = B.ID AND A.NAME = B.NAME