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

sqlÓïÑÔ£ºÈçºÎÅжÏ×Ö¶ÎÊÇ·ñ´æÔÚ£¬ÈçºÎɾ³ý¼°´´½¨×Ö¶Î

ÈçºÎÅжÏ×Ö¶ÎÊÇ·ñ´æÔÚ
 if col_length('±íÃû','×Ö¶Î1') is null  ALTER TABLE ±íÃû ADD ×Ö¶Î1 Nvarchar(50)  if col_length('±íÃû','×Ö¶Î2') is null  ALTER TABLE ±íÃû ADD ×Ö¶Î2 Nvarchar(50) ");
ɾ³ý×Ö¶Î
if col_length('±íÃû','×Ö¶Î1,') is not null  ALTER TABLE ±íÃû drop  column ×Ö¶Î1, column ×Ö¶Î2,column ×Ö¶Î3
´´½¨×Ö¶Î
 ALTER TABLE ±íÃû ADD ×Ö¶Î1 Nvarchar(50) , ×Ö¶Î2  INT NULL


Ïà¹ØÎĵµ£º

SQL¸ß¼¶Ó¦Óà Garin Zhang

×·¼Ó£ºrow_number, rank, dese_rank, ntile
1. row_number: Ϊ²éѯ³öÀ´µÄÿһÐмǼÉú³ÉÒ»¸öÐòºÅ¡£
SELECT row_number() OVER(ORDER BY field) AS row_n
from tablename;
·ÖÒ³²éѯ£º
with t_towtable
as (select row_number over(order by field1) as row_number from tb)
select * from t_rowtable where row_numbe ......

Ö´Ðлº´æÒÔÓÅ»¯SQL ServerµÄÄÚ´æÕ¼ÓÃ

×÷Õߣºsuperhasty
  2007-11-29
ÔÚÂÛ̳Éϳ£¼ûÓÐÅóÓѱ§Ô¹£¬ËµSQL ServerÌ«³ÔÄÚ´æÁË¡£ÕâÀï±ÊÕ߸ù¾Ý¾­Ñé¼òµ¥½éÉÜÒ»ÏÂÄÚ´æÏà¹ØµÄµ÷ÓÅ֪ʶ¡£Ê×ÏÈ˵Ã÷Ò»ÏÂSQL
ServerÄÚ´æÕ¼ÓÃÓÉÄ¿·Ö×é³É¡£SQL ServerÕ¼ÓõÄÄÚ´æÖ÷ÒªÓÉÈý²¿·Ö×é³É£ºÊý¾Ý»º´æ(Data
Buffer)¡¢Ö´Ðлº´æ(Procedure Cache)¡¢ÒÔ¼°SQL ServerÒýÇæ³ÌÐò¡£S ......

oracle sql tuning

alert index mem_ct monitoring usage;
desc v$object_usage;
set linesize 190
select * from v$object_usage;
SQL>SET AUTOTRACE ON;
¡¡¡¡*autotrace¹¦ÄÜÖ»ÄÜÔÚSQL*PLUSÀïʹÓÃ
¡¡¡¡ÆäËûһЩʹÓ÷½·¨£º
¡¡¡¡2.2.1¡¢ÔÚSQLPLUSÖеõ½Óï¾ä×ܵÄÖ´ÐÐʱ¼ä
¡¡¡¡SQL> set timing on;
2.2.2¡¢Ö»ÏÔʾִÐмƻ®--(»áÍ¬Ê ......
© 2009 ej38.com All Rights Reserved. ¹ØÓÚE½¡ÍøÁªÏµÎÒÃÇ | Õ¾µãµØÍ¼ | ¸ÓICP±¸09004571ºÅ