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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
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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'
        WHEN price < 10 THEN 'Bargain'
 &nb


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/* °üº¬CÍ·Îļþ */
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
/* °üº¬SQLCAÍ·Îļþ */
EXEC SQL INCLUDE sqlca;
EXEC SQL INCLUDE sqlda;
int main()
{
    EXEC SQL BEGIN DECLARE SECTION;
    int  money;
    ......

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