Ò׽ؽØͼÈí¼þ¡¢µ¥Îļþ¡¢Ãâ°²×°¡¢´¿ÂÌÉ«¡¢½ö160KB

sqlµÝ¹é²éѯ

ÔÚ¹¤×÷ÖÐÓöµ½Ò»¸öÎÊÌâ,ÊÇÐèÒªsqlµÝ¹é²éѯµÄ.²»¶®,ÓÚÊǵ½csdnÉÏÈ¥ÎÊ,ÄÇÀïµÄЧÂÊÕæÊǷdz£¸ß,ÎÒÒÔǰҲûÔÚÉÏÃæÎʹýÎÊÌâ.
ÎÊÌâÃèÊö:
ÎÒÓÐÒ»¸ö±í½á¹¹ÈçÏÂ:
id upperid
1     2
3     2
4     1
5     3
¾ßÌå²ã´Î²»ÖªµÀ,ÎÒÏëÓõݹésqlÓï¾ä°ÑËùÓÐÊôÓÚij¸öupperidµÄÊý¾Ý,°üÀ¨ËüµÄ×ÓÊ÷,¶¼¶Á³öÈ¥£¬ÇëÎÊÓ¦¸Ã×ÓÔõôд?     
±ÈÈç˵ upperid =2
ÄÇôÏÈÕÒµ½1,3,È»ºóÔÙÓÉ1,3ÕÒµ½4,5
ʹÓÃsqlÓï¾äʵÏÖ
ÓÐÁ½Î»ÅóÓѶ¼¸øÁ˻ظ´:
fa_ge(鶴嘯¾ÅÌì)
Create table t(id int,upperid int)
insert into t
select 1,     2
union all select 3,     2
union all select 4,     1
union all select 5,     3
select * from t
create function aa(@upperid int)
returns @t table (id int,upperid int,level int)
as
begin
declare @i int
set @i=1
insert into @t
select *,@i from t where upperid=@upperid
while @@rowcount>0
begin
set @i=@i+1
insert into @t
select a.*,@i from t a left join @t b on a.upperid=b.id
where b.level=@i-1
end
return
end
select * from dbo.aa(1)
id          upperid     level      
----------- ----------- -----------
4           1           1
£¨ËùÓ°ÏìµÄÐÐÊýΪ 1 ÐУ©
select * from dbo.aa(2)
id          upperid     level      
----------- ----------- -----------
1           2           1
3           2           1
4           1     &nbs


Ïà¹ØÎĵµ£º

ǶÈëSQLÓï¾ä

ǶÈëSQLÓïÑÔ:
ÎÒ½«Ò»¸ösqlÁ´½Óµ½Êý¾Ý¿â£¬¸ÃÊý¾Ý¿âÃûΪmaster(ϵͳÊý¾Ý¿â)
then ¸øÊý¾Ý¿âÌí¼ÓÐÂ±í£¬½¨Á¢Èý¸ökey£ºuserid(int),name(char(10)),password(char(10))
ÔÚ´°ÌåÖÐŪÈý¸ötextbox¿Ø¼þ£¬·Ö±ð¶¨ÒåNameÊôÐÔΪuserid,name,password;
ÔÙÀ´Ò»¸öbutton
ÒÔÏÂÊÇForm1.csÖеĴúÂë
 using System;
using System.Coll ......

SQL Server 2008¶¨Ê±×÷ÒµµÄÖƶ¨£¨SQL2005²Î¿¼´Ë·½·¨£©

SQL Server 2008 ¶¨Ê±×÷ÒµµÄÖƶ¨
--1.´ò¿ª¡¾SQL Server Management Studio¡¿£¬ÔÚ¡¾¶ÔÏó×ÊÔ´¹ÜÀíÆ÷¡¿ÁбíÖÐÑ¡Ôñ¡¾SQL Server ´úÀí¡¿£»
--2.Êó±êÓÒ»÷¡¾SQL Server ´úÀí¡¿£¬Ñ¡Ôñ¡¾Æô¶¯(S)¡¿£¬ÈçÒÑÆô¶¯£¬¿ÉÒÔÊ¡ÂԴ˲½Ö裻
--3.Õ¹¿ª¡¾SQL Server ´úÀí¡¿ÁÐ±í£¬ÓÒ»÷¡¾×÷Òµ¡¿-->¡¾Ð½¨×÷Òµ¡¿£»
--3.1 ÔÚ¡¾³£¹æ¡¿Ñ¡ÏÖУº ......

Oracle SQLÓï¾äÓÅ»¯·ÖÎö

¡¡²Ù×÷·ûÓÅ»¯
¡¡¡¡IN ²Ù×÷·û
¡¡¡¡ÓÃINд³öÀ´µÄSQLµÄÓŵãÊDZȽÏÈÝÒ×д¼°ÇåÎúÒ׶®£¬Õâ±È½ÏÊʺÏÏÖ´úÈí¼þ¿ª·¢µÄ·ç¸ñ¡£
¡¡¡¡µ«ÊÇÓÃINµÄSQLÐÔÄÜ×ÜÊDZȽϵ͵ģ¬´ÓORACLEÖ´ÐеIJ½ÖèÀ´·ÖÎöÓÃINµÄSQLÓë²»ÓÃINµÄSQLÓÐÒÔÏÂÇø±ð£º
¡¡¡¡ORACLEÊÔͼ½«Æäת»»³É¶à¸ö±íµÄÁ¬½Ó£¬Èç¹ûת»»²»³É¹¦ÔòÏÈÖ´ÐÐINÀïÃæµÄ×Ó²éѯ£¬ÔÙ²éѯÍâ²ãµÄ±í¼Ç¼£ ......

sql´óÊý¾Ý²Ù×÷ÈçºÎÓÅ»¯

¾ßÌåҪעÒâµÄ£º  
1.Ó¦¾¡Á¿±ÜÃâÔÚ where ×Ó¾äÖжÔ×ֶνøÐÐ null ÖµÅжϣ¬·ñÔò½«µ¼ÖÂÒýÇæ·ÅÆúʹÓÃË÷Òý¶ø½øÐÐÈ«±íɨÃ裬È磺  
select id from t where num is null  
¿ÉÒÔÔÚnumÉÏÉèÖÃĬÈÏÖµ0£¬È·±£±íÖÐnumÁÐûÓÐnullÖµ£¬È»ºóÕâÑù²éѯ£º  
select id from t where num=0 &n ......
© 2009 ej38.com All Rights Reserved. ¹ØÓÚE½¡ÍøÁªÏµÎÒÃÇ | Õ¾µãµØͼ | ¸ÓICP±¸09004571ºÅ