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

Ò»¸öSQLÃæÊÔÌâ

 ÌâÄ¿ÒªÇó
°¢ÀïbabaµÄÃæÊÔÌâ
ÓÐÈý¸ö±í
    ѧÉú±í  S 
          SID  SNAME
  ½Ìʦ¿Î±í T 
          TID  TNAME  TCL
  ³É¼¨±í  SC   
            SID  TCL  SCR
¸÷×ֶεĺ¬Òå²»ÓÃÎÒ±êÃ÷ÁË°É£¬´óÏÀ¸ç¸çô£¡ºÇºÇ
ÏÖÔÚÒªÇóдSQL²éѯ
    1¡¢Ñ¡ÐÞÁËA¡¢B¿Î³Ì£¬²¢ÇÒA¿Î³ÌµÄ³É¼¨´óÓÚB³É¼¨µÄѧÉúÐÕÃû£¿
    2¡¢Ã»ÓÐÑ¡ÐÞ‘li’ÀÏʦµÄ¿Î³ÌµÄѧÉú£¬ÒªÇó²»ÄÜÓÃin£¬exists µÈ´Ê£¿
create table SC(
SID varchar(64) ,
TCL varchar(64) ,
SCR int) ;
create table S (
SID varchar(64) ,
SNAME varchar(64)
) ;
create table T
(
  TID varchar(64),
  TNAME varchar(64),
  TCL varchar(64)
) ;
insert into S VALUES ('1','11') ;
insert into S VALUES ('2','22') ;
insert into S VALUES ('3','33') ;
insert into S VALUES ('4','44') ;
insert into SC VALUES ('1','a',100) ;
insert into SC VALUES ('1','b',90) ;
insert into SC VALUES ('2','a',77) ;
insert into SC VALUES ('3','b',34) ;
insert into SC VALUES ('4','a',59) ;
insert into SC VALUES ('4','b',88) ;
insert into T VALUES ('5','li','a');
µÚÒ»¸öÎÊÌâµÄ´ð°¸
select
  s.sname,sc1.scr,sc2.scr
from
  s,sc sc1,sc sc2 
where s.sid=sc1.sid
    and s.sid=sc2.sid
    and sc1.tcl='a'
    and sc2.tcl='b'
    and sc1.scr>sc2.scr
   
    ÔËÐнá¹û£º
   11 £¬100 £¬ 90
   
  µÚ¶þÌâµÄ´ð°¸
 
  select sid from
(select s.sid,a.tcl from (select sc.sid,sc.tcl  from sc,t where sc.tcl=t.tcl and t.tname='li' ) a
right join s
  on a.sid=s.sid ) b
where  b.tcl is null
ÔËÐнá¹û

   


Ïà¹ØÎĵµ£º

SQL ServerºÍOracle³£Óú¯Êý¶Ô±È


Êýѧº¯Êý
1.¾ø¶ÔÖµ
S:select abs(-1) value
O:select abs(-1) value from dual
2.È¡Õû(´ó)
S:select ceiling(-1.001) value
O:select ceil(-1.001) value from dual
3.È¡Õû£¨Ð¡£©
S:select floor(-1.001) value
O:select floor(-1.001) value from dual
4.È¡Õû£¨½ØÈ¡£©
S:select cast(-1.002 as in ......

¶¯Ì¬SQL

Sample1:
/* Variable Declaration */
DECLARE @EmpID AS SMALLINT
DECLARE @SQLQuery AS NVARCHAR(500)
/* Build and Execute a Transact-SQL String with a single parameter value Using EXECUTE Command */
SET @EmpID = 1001
SET @SQLQuery = 'SELECT * from tblEmployees WHERE EmployeeID = ' + CAST(@EmpID A ......

ÕÒµ½ÒýÆð´ÅÅÌÅÅÐòµÄSQL

ÏÂÃæµÄÕâЩ½Å±¾¶¼¿ÉÒÔÕÒµ½ÒýÆð´ÅÅÌÅÅÐòµÄSQL¡£ 
SELECT /*+ rule */ DISTINCT a.SID, a.process, a.serial#,
TO_CHAR (a.logon_time, 'YYYYMMDD HH24:MI:SS') LOGON, a.osuser,TABLESPACE, b.sql_text
from v$session a, v$sql b, v$sort_usage c
WHERE a.sql_address = b.address AND a.saddr = c.session_addr; ......

¾¡Á¿²»ÒªÆ´´ÕSqlÓï¾ä,ÓòÎÊýÀ´·À×¢Èë

    Èç¹ûÊÇÀàËÆ"select   *   from   user   where   uid="+uid +"  and   pwd="+pwd ºÜÈÝÒ׳öÎÊÌâ
    ʹÓà   SQLParamenter      
    °ÑÄãµÄSQLÓï¾äд³É   ÀàËÆ´æ´¢¹ý³Ì   ......

SQL ÁÙʱ±íÓëÁÙʱ±äÁ¿±í

 
         ÔÚSQLServerµÄÐÔÄܵ÷ÓÅÖУ¬ÓÐÒ»¸ö²»¿É±ÈÄâµÄÎÊÌ⣺ÄǾÍÊÇÈçºÎÔÚÒ»¶ÎÐèÒª³¤Ê±¼äµÄ´úÂë»ò±»Æµ·±µ÷ÓõĴúÂëÖд¦ÀíÁÙʱÊý¾Ý¼¯?±í±äÁ¿ºÍÁÙʱ±íÊÇÁ½ÖÖÑ¡Ôñ¡£ÈçºÎÈ·¶¨Ê²Ã´Ê±ºòÓÃÁÙʱ±í£¬Ê²Ã´Ê±ºòÓñí±äÁ¿ÄØ£¿ÁÙʱ±íºÍ±í±äÁ¿¶¼ÓÐÌض¨µÄÊÊÓû·¾³¡£
¡¡¡¡±í±äÁ¿
¡¡¡¡±äÁ¿¶ ......
© 2009 ej38.com All Rights Reserved. ¹ØÓÚE½¡ÍøÁªÏµÎÒÃÇ | Õ¾µãµØͼ | ¸ÓICP±¸09004571ºÅ