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

SQLÊäÈëÊý¾Ý,Ö¸¶¨ÅÅÐò˳Ðò

·Ï»°²»¶à˵,ÉÏ´úÂë
SELECT k
from (
SELECT 'shanghai' AS k from DUAL
UNION ALL
SELECT 'dalian' AS k from DUAL
UNION ALL
SELECT 'beijing' AS k from DUAL
)
ORDER BY CASE
WHEN k = 'beijing'
THEN 1
WHEN k = 'dalian'
THEN 3
WHEN k = 'shanghai'
THEN 2
END 
ÀûÓÃORDER BY µÄcaseÓï¾äÅäÖÃÅÅÐò˳ÐòºÅ.
µ±È»ÀûÓÃÀûÓòéѯ×Ó±í,»òunionµÈ·½Ê½Ò²¿ÉÒÔ,µ«ÊÇÕâ¸ö¿ÉÒÔ˵ÊÇ×î¼òµ¥,×î¸ßЧ·½·¨.


Ïà¹ØÎĵµ£º

¸ßЧSQL²éѯ֮Ë÷Òý£¨V£©

ÏÈÕ¾ÔÚÓ¦ÓóÌÐòµÄ½Ç¶È˵˵ËüÃǵIJ»Í¬¡£
1¡¢  Ö±½ÓÆ´ SQL
¾ÍÏñ´ó¼ÒÁ˽âµÄÄÇÑù£¬Ö±½ÓÆ´ SQL ´øÀ´ÁË SQL ×¢Èë¹¥»÷£¬´øÀ´ÁËƴʱЩÐíµÄÐÔÄÜËðʧ£¬µ«ÊÇÆ´²»ÓÃÌí¼Ó SqlParameter £¬»áÉÙдºÜ¶à´úÂë——ºÜ¶àÈËϲ»¶Ö±½ÓÆ´£¬Ò²Ðí¾ÍÒòΪÕâµã¡£ÕâÖÖ×ö·¨»á°ÑÄãÆ´ºÃµÄ SQL Ô­ÑùÖ±½Ó·¢Ë͵½ DB ·þÎñÆ÷È¥Ö´ÐС££¨×¢ÒâÀàËÆ ......

¸ßЧSQL²éѯ֮Ë÷Òý¸²¸Ç(index coverage)

½ñÌì×öSQL ÓÅ»¯£¬²éÕÒÖ´Ðмƻ®Ê±£¬Ö´Ðмƻ®£¬·¢ÏÖ´ËÖ´Ðмƻ®ÓëÒÔÍùµÄ¼Æ»®ÓÐËùÇø±ð£»ÕÒ¼»¥ÁªÍø£¬ÖÕÓÚÕÒһƪÓйØÑо¿±È½ÏÉîÈëµÄÎÄÕ£»
Ô­Ö´Ðмƻ®Ê¹ÓõÄÊÇË÷ÒýɨÃ裬ͻȻһÏ»áʹÓÃË÷Òý¸²¸Ç¼¼Êõ£¬Ð§ÂÊ´óÔö£»
SELECT * µÄÕæÏࣺË÷Òý¸²¸Ç(index coverage)
SELECT *µÄЧÂʺÜÔã¸âÂ𣿵±È»£¬ËùÓÐÈ˶¼ÖªµÀÕâÒ»µã£¬µ«ÊÇΪʲôÄØ£ ......

SQL Server 2005 ÖеķÖÇø±íºÍË÷Òý(1)


¹ØÓÚ±¾Îı¾ÎÄËùÃè»æµÄ¹¦Äܺͼƻ®ÊÇÏÂÒ»°æ±¾ SQL Server µÄ¿ª·¢·½Ïò¡£ËüÃDz¢·Ç±¾²úÆ·µÄ˵Ã÷Ê飬ÈçÓиü¸Ä£¬Ë¡²»ÁíÐÐ֪ͨ¡£¶ÔÓÚ×îÖÕ²úÆ·ÊÇ·ñ¾ßÓÐÕâЩ¹¦Äܲ»×öÈκÎÃ÷ʾ»ò°µÊ¾µÄ±£Ö¤¡£¶ÔÓÚijЩ¹¦ÄÜ£¬±¾ÎļÙÉè¶ÁÕßÊìϤ SQL Server 2000 ¹¦ÄܺͷþÎñ¡£Óйر³¾°ÐÅÏ¢£¬Çë·ÃÎÊSQL Server ÍøÕ¾»ò SQL Server 2000 ×ÊÔ´¹¤¾ß°ü¡£Õâ²¢²»Ê ......

SQL Server 2005 ÖеķÖÇø±íºÍË÷Òý [2]

·ÖÇøµÄ·¢Õ¹ÀúÊ·
·ÖÇøµÄ¸ÅÄî¶Ô SQL Server À´Ëµ²¢²»Ä°Éú¡£Êµ¼ÊÉÏ£¬´Ë²úÆ·µÄÿ¸ö°æ±¾Öж¼¿ÉÒÔʵÏÖ²»Í¬ÐÎʽµÄ·ÖÇø¡£µ«ÊÇ£¬ÓÉÓÚûÓÐΪÁË°ïÖúÓû§´´½¨ºÍά»¤·ÖÇø¼Ü¹¹¶øרÃÅÉè¼ÆһЩ¹¦ÄÜ£¬Òò´Ë·ÖÇøÒ»Ö±ÊÇÒ»¸öºÜ·±ËöµÄ¹ý³Ì£¬Ã»Óеõ½³ä·ÖµÄÀûÓ᣶øÇÒ£¬Óû§ºÍ¿ª·¢ÈËÔ±¶Ô´Ë¼Ü¹¹´æÔÚÎó½â£¨ÓÉÓÚÆäÊý¾Ý¿âÉè¼Æ±È½Ï¸´ÔÓ£©£¬µÍ¹ÀÁËËüµÄÓÅ ......

sqlÖÐdatediffºÍdateaddµÄÓ÷¨

ͨ³££¬ÄãÐèÒª»ñµÃµ±Ç°ÈÕÆںͼÆËãһЩÆäËûµÄÈÕÆÚ£¬ÀýÈ磬ÄãµÄ³ÌÐò¿ÉÄÜÐèÒªÅжÏÒ»¸öÔµĵÚÒ»Ìì»òÕß×îºóÒ»Ìì¡£ÄãÃǴ󲿷ÖÈË´ó¸Å¶¼ÖªµÀÔõÑù°ÑÈÕÆÚ½øÐзָÄê¡¢Ô¡¢Èյȣ©£¬È»ºó½ö½öÓ÷ָî³öÀ´µÄÄê¡¢Ô¡¢ÈյȷÅÔÚ¼¸¸öº¯ÊýÖмÆËã³ö×Ô¼ºËùÐèÒªµÄÈÕÆÚ£¡
¡¡¡¡ÔÚÕâƪÎÄÕÂÀÎÒ½«¸æËßÄãÈçºÎʹÓÃDATEADDºÍDATEDIFFº¯ÊýÀ´¼ÆËã³öÔÚÄã ......
© 2009 ej38.com All Rights Reserved. ¹ØÓÚE½¡ÍøÁªÏµÎÒÃÇ | Õ¾µãµØͼ | ¸ÓICP±¸09004571ºÅ