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

ʹÓÃSQL²éѯ±í×Ö¶ÎÁеı¸×¢ÐÅÏ¢

ÓÃÏÂÃæµÄÊÓͼ£º
SQL> desc user_col_comments;
  Name                            Null?    Type
  ------------------------------- -------- ----
  TABLE_NAME                      NOT NULL VARCHAR2(30)
  COLUMN_NAME                     NOT NULL VARCHAR2(30)
  COMMENTS                                 VARCHAR2(4000)
²éѯ±í×Ö¶ÎÁеı¸×¢ÐÅÏ¢¡£
  
±ÈÈçÔÚ´´½¨±íTEST µÄʱºò£¬ÎªNAMEÁÐдÁ˱¸×¢“ÐÕÃû£º”ÏÖÔÚ¿ÉÒÔÖ±½Ó°ÑNAMEÁеı¸×¢¶Á³öÀ´Ð´µ½³ÌÐòµÄ¿Ø¼þÖУ¬»ñÈ¡·½·¨ÈçÏ£º
select comments  
from user_col_comments  
where table_name = 'TEST'
and column_name = 'NAME';


Ïà¹ØÎĵµ£º

MySQL ×Ö·û¼¯µ¼ÖÂSQLÁ¬½ÓÖ®ºóÖÐÎÄÂÒÂëµÄÎÊÌ⣡

character-set-server = GB2312
collation-server = latin1_general_ci
MySQL×Ö·û¼¯ GBK¡¢GB2312¡¢UTF8Çø±ð ½â¾ö MYSQLÖÐÎÄÂÒÂëÎÊÌâ ÊÕ²Ø
MySQLÖÐÉæ¼°µÄ¼¸¸ö×Ö·û¼¯
character-set-server/default-character-set£º·þÎñÆ÷×Ö·û¼¯£¬Ä¬ÈÏÇé¿öÏÂËù²ÉÓõġ£
character-set-database£ºÊý¾Ý¿â×Ö·û¼¯¡£
character-set-table£ºÊ ......

SQLSERVER SQLÐÔÄÜÓÅ»¯

1.Ñ¡Ôñ×îÓÐЧÂʵıíÃû˳Ðò(Ö»ÔÚ»ùÓÚ¹æÔòµÄÓÅ»¯Æ÷ÖÐÓÐЧ)¡¡¡¡
¡¡¡¡ SQLSERVERµÄ½âÎöÆ÷°´ÕÕ´ÓÓÒµ½×óµÄ˳Ðò´¦Àífrom×Ó¾äÖеıíÃû£¬Òò´Ëfrom×Ó¾äÖÐдÔÚ×îºóµÄ±í£¨»ù´¡±ídriving table£©½«±»×îÏÈ´¦Àí£¬ÔÚfrom×Ó¾äÖаüº¬¶à¸ö±íµÄÇé¿öÏ£¬±ØÐëÑ¡Ôñ¼Ç¼ÌõÊý×îÉٵıí×÷Ϊ»ù´¡±í£¬µ±SQLSERVER´¦Àí¶à¸ö±íʱ£¬»áÔËÓÃÅÅÐò¼°ºÏ²¢µÄ·½Ê½Á ......

sql server2005Öзֶβéѯ¼Ç¼µÄsql¡£

Êý¾Ý¿â±íµÄ¼Ç¼Èç¹ûÌ«¶à£¬±ÈÈç´ïµ½ÁË20ÍòÒÔÉÏ£¬ÔÚbosÖÐÒ»´ÎÐÔ²é¼Ç¼×ö´¦Àí¿ÉÄÜ»á³öÏÖoutofmemoryµÄ´íÎó£¬ÎÒÃÇÖ»ÄܲÉÈ¡·Ö¶ÎÈ¡¼Ç¼À´´¦Àí£¬¾ßÌåʾÀýÈçÏ£º
/*dialect*/
With Cust AS 
( SELECT fnumber,
ROW_NUMBER() OVER (order by fnumber) as RowNumber  ......

Oracle SQLµÄÓÅ»¯


SQLµÄÓÅ»¯Ó¦¸Ã´Ó5¸ö·½Ãæ½øÐе÷Õû£º
1.È¥µô²»±ØÒªµÄ´óÐͱíµÄÈ«±íɨÃè
2.»º´æСÐͱíµÄÈ«±íɨÃè
3.¼ìÑéÓÅ»¯Ë÷ÒýµÄʹÓÃ
4.¼ìÑéÓÅ»¯µÄÁ¬½Ó¼¼Êõ
5.¾¡¿ÉÄܼõÉÙÖ´Ðмƻ®µÄCost
SQLÓï¾ä£º
ÊǶÔÊý¾Ý¿â(Êý¾Ý)½øÐвÙ×÷µÄΩһ;¾¶£»
ÏûºÄÁË70%~90%µÄÊý¾Ý¿â×ÊÔ´£»¶ÀÁ¢ÓÚ³ÌÐòÉè¼ÆÂß¼­£¬Ïà¶ÔÓÚ¶Ô³ÌÐòÔ´´úÂëµÄÓÅ»¯£¬¶ÔSQLÓï¾äµÄÓÅ» ......

SQLÓï¾äÓÅ»¯·½·¨

1.Ö»²éѯÐèÒªµÄÁУ¬²»ÓÃ*
2.INÊʺÏÓÚÍâ±í´ó¶øÄÚ±íСµÄÇé¿ö£»EXISTSÊʺÏÓÚÍâ±íС¶øÄÚ±í´óµÄÇé¿ö 1¡¢Éý¼¶Ó²¼þ
2¡¢¸ù¾Ý²éѯÌõ¼þ,½¨Á¢Ë÷Òý,ÓÅ»¯Ë÷Òý¡¢ÓÅ»¯·ÃÎÊ·½Ê½£¬ÏÞÖƽá¹û¼¯µÄÊý¾ÝÁ¿¡£
3¡¢À©´ó·þÎñÆ÷µÄÄÚ´æ
4¡¢Ôö¼Ó·þÎñÆ÷CPU¸öÊý
5¡¢¶ÔÓÚ´óµÄÊý¾Ý¿â²»ÒªÉèÖÃÊý¾Ý¿â×Ô¶¯Ôö³¤£¬Ëü»á½µµÍ·þÎñÆ÷µÄÐÔÄÜ ......
© 2009 ej38.com All Rights Reserved. ¹ØÓÚE½¡ÍøÁªÏµÎÒÃÇ | Õ¾µãµØͼ | ¸ÓICP±¸09004571ºÅ