ÀûÓÃoracleÉ󼯹¦ÄÜÀ´¼à¿Ø²âÊÔÊý¾Ý¿âµÄ±ä»¯
ÀûÓÃoracleÉ󼯹¦ÄÜÀ´¼à²âÊÔ»·¾³µÄ±ä»¯
×ö¹ý²âÊÔµÄÈ˶¼Ó¦¸Ã»áÅöµ½ÕâÑùµÄÇé¿ö£º²âÊÔ·¢ÏÖµÄbugÔÚ¿ª·¢»úÆ÷ÉÏûÓгöÏÖ£¬ÏÔÈ»ÕâÊÇ»·¾³²îÒìµÄÔÒò¡£Ï൱¶àÇé¿öÏ£¬ÒòΪ²âÊÔʹÓõÄÊý¾Ý¿â½á¹¹ºÍ¿ª·¢Ê¹ÓõÄÊý¾Ý¿â½á¹¹²»Ò»ÖÂÔì³ÉµÄ¡£ÓÈÆäÊÇһЩ¹«Ë¾ÔÚÌá½»²âÊÔ°æ±¾µÄʱºò£¬×¢ÖØÓ¦ÓóÌÐòµÄ°æ±¾Ìá½»£¬ÍùÍùºöÂÔÌá½»ºÍ³ÌÐòÆ¥ÅäµÄÊý¾Ý¿â½á¹¹£¬ÔÚÕâÖÖÇé¿öÏ£¬Èç¹û³ÌÐòºÍÊý¾Ý¿â½á¹¹²»Æ¥ÅäµÄ»°£¬ÏµÍ³Îȶ¨¾Í¹ÖÁË£¬¾ÍÏñwindowsûÓжÔÓ¦µÄ×¢²á±íÒ»Ñù£¬ÄÜÎȶ¨Âð£¿
»Øµ½ÕýÌ⣬Èç¹û²ÉÓÃoracle×÷Ϊµ×²ãÊý¾Ý¿âµÄϵͳ£¬ÈçºÎ±ÜÃâÕâÖÖÇé¿öÄØ£¿Æäʵ£¬OracleµÄÉ󼯹¦ÄܳýÁËÓÃÓÚ°²È«ÐÔ¼ì²éÖ®Í⣬·Åµ½²âÊÔÁìÓòÔòÓÐÒ»¸öºÃ´¦£¬¾ÍÊÇ¼à¿Ø²âÊÔÊý¾Ý¿âµÄ±ä»¯Çé¿ö¡£OracleÉó¼ÆÄÚÈݺܷḻ£º°üÀ¨Óï¾äÉ󼯡¢¶ÔÏóÉ󼯡¢Ï¸Á£¶ÈÉ󼯣¨FGA£©£¬¼à¿ØÊý¾Ý¿â»·¾³µÄ±ä»¯£¬Ö»ÒªÓõ½Óï¾äÉó¼ÆºÍ¶ÔÏóÉ󼯼´¿É¡£
Ê×ÏÈ£ºÐèÒª¼ì²éÊý¾Ý¿â·þÎñÆ÷ÊÇ·ñ¿ªÆôÁËÉ󼯣¬²ÉÓÃshow parameter audÃüÁî¡£
Oracle Database 11g Enterprise Edition Release 11.1.0.6.0 - Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
SQL> show parameter aud
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
audit_file_dest string F:\APP\ADMINISTRATOR\ADMIN\ORC L\ADUMP
audit_sys_operations boolean FALSE
audit_trail string FALSE
Èç¹ûaudit_trail = FALSE»òÕßnone£¬Ôò±íÃ÷ûÓпªÆôÉ󼯹¦ÄÜ£¬ÐèÒª¿ªÆôÉ󼯹¦ÄÜ£¬ÎªÁ˽¨Á
Ïà¹ØÎĵµ£º
select distinct id
from table t
where rownum < 10
order by t.id desc;
ÉÏÊöÓï¾äµÄ¹ýÂËÌõ¼þÖ´ÐÐ˳Ðò ÏÈwhere --->order by --->distinct
Èç¹ûÓÐgroup byµÄ»° group by ÔÚorder byÇ°ÃæµÄ ......
ʲôÊǺϲ¢¶àÐÐ×Ö·û´®£¨Á¬½Ó×Ö·û´®£©ÄØ£¬ÀýÈ磺
SQL> desc test;
Name Type Nullable Default Comments
------- ------------ -------- ------- --------
COUNTRY VARCHAR2(20) Y &nb ......
ʲôÊǺϲ¢¶àÐÐ×Ö·û´®£¨Á¬½Ó×Ö·û´®£©ÄØ£¬ÀýÈ磺
SQL> desc test;
Name Type Nullable Default Comments
------- ------------ -------- ------- --------
COUNTRY VARCHAR2(20) Y &nb ......
1£¬segments µÄ·ÖÀà
l
Êý¾Ý¶Î
l
Ë÷Òý¶Î
l
ÁÙʱ¶Î
l
»ØÍË ......
SOURCE: CLICK HERE
±¾ÎĽ²ÊöSQL Server¡¢Oracle¡¢MySQL²é³öֵΪNULLµÄÌæ»»¡£
ÔÚSQL Server Oracle MySQLµ±Êý¾Ý¿âÖвé³öijֵΪNULLÔõô°ì?
1¡¢MSSQL: ISNULL()
Óï·¨
ISNULL ( check_expression , replacement_value )
²ÎÊý
check_expression
½«±»¼ì²éÊÇ·ñΪ NULLµÄ±í´ïʽ¡£check_expression ¿ÉÒÔÊÇÈκÎÀàÐ͵ġ£
re ......