Ò׽ؽØÍ¼Èí¼þ¡¢µ¥Îļþ¡¢Ãâ°²×°¡¢´¿ÂÌÉ«¡¢½ö160KB

sqlÓïÑÔÖеÄcase when £¨À´×ÔÎÒ×ð¾´µÄһλÀÏʦСF£©

sqlÓïÑÔÖÐÓÐûÓÐÀàËÆCÓïÑÔÖеÄswitch caseµÄÓï¾ä£¿£¿
  ûÓÐ,ÓÃcase   when   À´´úÌæ¾ÍÐÐÁË.  
      
  ÀýÈç,ÏÂÃæµÄÓï¾äÏÔʾÖÐÎÄÄêÔ  
   
  select   getdate()   as   ÈÕÆÚ,case   month(getdate())  
  when   11   then   'ʮһ'  
  when   12   then   'Ê®¶þ'  
  else   substring('Ò»¶þÈýËÄÎåÁùÆß°Ë¾ÅÊ®',   month(getdate()),1)  
  end+'ÔÂ'   as   Ô·Ý
=====================================================================
CASE ¿ÉÄÜÊÇ SQL Öб»ÎóÓÃ×î¶àµÄ¹Ø¼ü×ÖÖ®Ò»¡£ËäÈ»Äã¿ÉÄÜÒÔǰÓùýÕâ¸ö¹Ø¼ü×ÖÀ´´´½¨×ֶΣ¬µ«ÊÇËü»¹¾ßÓиü¶àÓ÷¨¡£ÀýÈ磬Äã¿ÉÒÔÔÚ WHERE ×Ó¾äÖÐʹÓà CASE¡£
 
Ê×ÏÈÈÃÎÒÃÇ¿´Ò»Ï CASE µÄÓï·¨¡£ÔÚÒ»°ãµÄ SELECT ÖУ¬ÆäÓï·¨ÈçÏ£º
 
SELECT <myColumnSpec> =
CASE
WHEN <A> THEN <somethingA>
WHEN <B> THEN <somethingB>
ELSE <somethingE>
END
 
ÔÚÉÏÃæµÄ´úÂëÖÐÐèÒªÓþßÌåµÄ²ÎÊý´úÌæ¼âÀ¨ºÅÖеÄÄÚÈÝ¡£ÏÂÃæÊÇÒ»¸ö¼òµ¥µÄÀý×Ó£º
 
USE pubs
GO
SELECT
     Title,
    'Price Range' =
    CASE
        WHEN price IS NULL THEN 'Unpriced'
        WHEN price < 10 THEN 'Bargain'
        WHEN price BETWEEN 10 and 20 THEN 'Average'
        ELSE 'Gift to impress relatives'
    END
from titles
ORDER BY price
GO
 
ÕâÊÇ CASE µÄµäÐÍÓ÷¨£¬µ«ÊÇʹÓà CASE Æäʵ¿ÉÒÔ×ö¸ü¶àµÄÊÂÇé¡£±È·½ËµÏÂÃæµÄ GROUP BY ×Ó¾äÖÐµÄ CASE£º
 
SELECT 'Number of Titles', Count(*)
from titles
GROUP BY
    CASE
        WHEN price IS NULL THEN 'Unpriced'
 &n


Ïà¹ØÎĵµ£º

º½¿Õ¹«Ë¾¹ÜÀíϵͳ(VC++ ÓëSQL 2005)

ϵͳ»·¾³£ºWindows 7
Èí¼þ»·¾³£ºVisual C++ 2008 SP1 +SQL Server 2005
±¾´ÎÄ¿µÄ£º±àдһ¸öº½¿Õ¹ÜÀíϵͳ
      ÕâÊÇÊý¾Ý¿â¿Î³ÌÉè¼ÆµÄ³É¹û£¬ËäÈ»³É¼¨²»¼Ñ£¬µ«ÊÇ×÷ΪÎÒÓÃVC++ ÒÔÀ´±àдµÄ×î´ó³ÌÐò»¹ÊÇ´«µ½ÍøÉÏ£¬ÒÔ¹©²Î¿¼¡£ÓÃVC++ ×öÊý¾Ý¿âÉè¼Æ²¢²»ÈÝÒ×£¬µ«Ò²²»ÊDz»¿ÉÄÜ¡£ÒÔÏÂÊÇÎҵijÌÐò½çÃæ£¬ºóÃæ ......

SQL 92 ±ê×¼ YoYo

        ÏîÄ¿ÖÕÓÚ½áÊøÁË£¬×ܽáµÄʱºòµ½ÁË... hehe :)
        ÔÚÏîÄ¿ÖÐÎÒÃÇÓöµ½Á˺ܶàµÄÎÊÌ⣬±ê×¼SQLʹÓþÍÊÇÆäÖÐÒ»¸ö¡£ ÒòΪÎÒÃÇÔÚ×öBI packageµÄʱºò£¬Ò»¿ªÊ¼¶¼ÊÇ»ùÓÚMS SQL À´×öµÄ£¬ËùÒÔUniverseµÄÉè¼ÆÉÏҲûÓÐÌ«¶àµÄ¿¼ÂÇ¡£ µ±ºóÀ´ÀÏ´ó¸æËßÎÒÅ ......

Hibernate,java,sqlÀàÐ͵ĶÔÓ¦¹ØÏµ


JavaÊý¾ÝÀàÐÍ
HibernateÊý¾ÝÀàÐÍ
±ê×¼SQLÊý¾ÝÀàÐÍ
byte
byte
TINYINT
short
short
SMALLINT
int
integer
INGEGER
long
long
BIGINT
float
float
FLOAT
double
double
DOUBLE
java.math.BigDecimal
big_decimal
NUMERIC
char, java.lang.Character
character
CHAR(1)
boolean, java.lang.Boole ......

SQLÓï¾ä ´´½¨±í

1.¶¨Òå»ù±¾±íÓï¾ä
    Óï·¨£º
    USE Êý¾Ý¿âÃû CREATE TABLE ±íÃû (ÁÐÃû ÀàÐÍ(´óС) DEFAULT'ĬÈÏÖµ',
                            & ......

PL/SQLÓû§Ö¸ÄÏÓë²Î¿¼ PL/SQLÓ¦ÓóÌÐòÐÔÄܵ÷ÓÅ£¨×ª£©

µÚÊ®¶þÕ PL/SQLÓ¦ÓóÌÐòÐÔÄܵ÷ÓÅ
1¡¢PL/SQLÐÔÄÜÎÊÌâµÄÔµÓÉ
Ó¦»ùÓÚPL/SQLµÄÓ¦ÓóÌÐòÊ©ÐÐЧÂʵÍÏÂʱ£¬Í¨³£ÊÇÒòΪ²»ºÃµÄSQL»°Óï¡¢±à³Ì²½Ö裬¶ÔPL/SQL»ù´¡ÕÆÎÕÔã¸â»òÊÇÂÒÓù²ÏíÄÚ´æ´¢Æ÷´Ù³ÉµÄ¡£
•PL/SQLÖв»ºÃµÄSQL»°Óï
PL/SQL±à³Ì¿´ÉÏÈ¥Ïà¶ÔÕսϼòµ¥£¬ÓÉÓÚËüÃǵĸ´ÔÓÄÚÈݶ¼ÑÚ²ØÔÚSQL»°ÓïÖУ¬SQL»°Óï¾­³£·Öµ£´óÁ¿µÄ ......
© 2009 ej38.com All Rights Reserved. ¹ØÓÚE½¡ÍøÁªÏµÎÒÃÇ | Õ¾µãµØÍ¼ | ¸ÓICP±¸09004571ºÅ