oracle distinct
oracle distinct
¹Ø¼ü×Ö: distinctµÄһЩÔÓ̸
distinctÕâ¸ö¹Ø¼ü×ÖÀ´¹ýÂ˵ô¶àÓàµÄÖØ¸´¼Ç¼ֻ±£ÁôÒ»Ìõ£¬µ«ÍùÍùÖ»Óà ËüÀ´·µ»Ø²»Öظ´¼Ç¼µÄÌõÊý£¬¶ø²»ÊÇÓÃËüÀ´·µ»Ø²»ÖؼǼµÄËùÓÐÖµ¡£ÆäÔÒòÊÇdistinctÖ»ÓÐÓöþÖØÑ»·²éѯÀ´½â¾ö£¬¶øÕâÑù¶ÔÓÚÒ»¸öÊý¾ÝÁ¿·Ç³£´óµÄÕ¾À´Ëµ£¬ÎÞÒÉÊÇ»áÖ±½ÓÓ°Ï쵽ЧÂʵġ£
ÏÂÃæÏÈÀ´¿´¿´Àý×Ó£º
table±í
×Ö¶Î1 ×Ö¶Î2
id name
1 a
2 b
3 c
4 c
5 b
¿â½á¹¹´ó¸ÅÕâÑù£¬ÕâÖ»ÊÇÒ»¸ö¼òµ¥µÄÀý×Ó£¬Êµ¼ÊÇé¿ö»á¸´Ôӵöࡣ
±ÈÈçÎÒÏëÓÃÒ»ÌõÓï¾ä²éѯµÃµ½name²»Öظ´µÄËùÓÐÊý¾Ý£¬ÄǾͱØÐëʹÓÃdistinctÈ¥µô¶àÓàµÄÖØ¸´¼Ç¼¡£
select distinct name from table
µÃµ½µÄ½á¹ûÊÇ:
----------
name
a
b
c
ºÃÏñ´ïµ½Ð§¹ûÁË£¬¿ÉÊÇ£¬ÎÒÏëÒªµÃµ½µÄÊÇidֵĨ£¿¸ÄһϲéѯÓï¾ä°É:
select distinct name, id from table
½á¹û»áÊÇ:
----------
id name
1 a
2 b
3 c
4 c
5 b
distinctÔõôûÆð×÷Óã¿×÷ÓÃÊÇÆðÁ˵쬲»¹ýËûͬʱ×÷ÓÃÁËÁ½¸ö×ֶΣ¬Ò²¾ÍÊDZØÐëµÃidÓëname¶¼ÏàͬµÄ²Å»á±»Åųý¡£¡£¡£¡£¡£¡£¡£
ÎÒÃÇÔٸĸIJéѯÓï¾ä:
select id, distinct name from table
ºÜÒź¶£¬³ýÁË´íÎóÐÅÏ¢ÄãʲôҲµÃ²»µ½£¬distinct±ØÐë·ÅÔÚ¿ªÍ·¡£Äѵ½²»ÄܰÑdistinct·Åµ½whereÌõ¼þÀÄÜ£¬ÕÕÑù±¨´í¡£
------------------------------------------------------------------------------------------------------------
ÏÂÃæ·½·¨¿ÉÐÐ:
select *, count(distinct name) from table group by name
½á¹û:
id name count(distinct name)
1 a 1
2 b 1
3 c 1
×îºóÒ»ÏîÊǶàÓàµÄ£¬²»ÓùܾÍÐÐÁË£¬Ä¿µÄ´ïµ½¡£¡£¡£¡£¡£
group by ±ØÐë·ÅÔÚ order by ºÍ limit֮ǰ£¬²»È»»á±¨´í
================
Ïà¹ØÎĵµ£º
SQL*LOADERÊÇORACLEµÄÊý¾Ý¼ÓÔØ¹¤¾ß£¬Í¨³£ÓÃÀ´½«²Ù×÷ϵͳÎļþÇ¨ÒÆµ½ORACLEÊý¾Ý¿âÖС£SQL*LOADERÊÇ´óÐÍÊý¾Ý
²Ö¿âÑ¡ÔñʹÓõļÓÔØ·½·¨¡£
¡¡¡¡ÔÚNTÏ£¬SQL*LOADERµÄÃüÁîΪSQLLDR£¬ÔÚUNIXÏÂÒ»°ãΪsqlldr/sqlload¡£
¡¡¡¡ÈçÖ´ÐУºd:\oracle>sqlldr
SQL*Loader: Release 8.1.6.0.0 - Production on ÐÇÆÚ¶þ 1ÔÂ 8 11:06:42 2 ......
Navicat for xxx ÊÇÒ»¸öÓÅÐãµÄÊý¾Ý¿â¹ÜÀí¿Í»§¶Ë£¬ÓÐ MySQL¡¢Oracle µÈ°æ±¾¡£½¨Òé´ó¼Ò×îºÃÓà Enterprise °æ±¾£¬¹¦ÄÜÈ«ÃæÒ»Ð©£¬µ«½ÏÖ®ÓÚÃâ·ÑµÄ Lite °æ£¬ÆóÒµ°æ¿ÉÊÇÒª»¨Òø×ÓÂòµÄ¡£
°²×° Navicat for Oracle ºó£¬Ê×ÏÈÐèÒª½¨Ò»¸ö“Á¬½Ó”£¬×÷Ϊij¸ö¹ÜÀíÈÎÎñµÄ±êʶ£¬ÒòΪ×÷Î ......
oracleÁ¬½ÓÊý¾Ý¿â²âÊÔ´úÂë
/**
*
* ˵Ã÷£º
* £¨1£©±¾ÀýʹÓÃJDBC_ODBCÇŽøÐÐÊý¾Ý¿âÁ¬½Ó£¬¹Ê´ËÐèÒªODBCÊý¾ÝÔ´
* £¨2£©±¾ÀýÖÐSQLΪ¸üÐÂÓï¾ä£¬¹Ê´ËʹÓÃÔØÌåµÄexecuteUpdate·½·¨£¬²¢ÇÒ·µ»ØÊÜÓ°Ïì¼Ç¼Êý
* (3) ÅäÖÃÁ¬½ÓORACLEµÄodbcÊý¾ÝÔ´ora
*/ ......
--´´½¨±í¿Õ¼ä
create tablespace Ãû³Æ
(
datafile='·¾¶\Ãû³Æ.ora',
size='50M',
autoextend='on'
)
/
--´´½¨ÁÙʱ±í¿Õ¼ä
create temporary tablespace Ãû³Æ
(
tempfile='·¾¶\Ãû³Æ.ora',
size='50M',
autoextend='on'
)
/
--´´½¨Óû§
create user Óû§Ãû idtenified by ÃÜÂë
/
--ΪÓû§Ö¸¶¨ ......
1.ÔÚORACLEÖÐʵÏÖSELECT TOP N
ÓÉÓÚORACLE²»Ö§³ÖSELECT TOPÓï¾ä£¬ËùÒÔÔÚORACLEÖо³£ÊÇÓÃORDER BY¸úROWNUMµÄ×éºÏÀ´ÊµÏÖSELECT TOP NµÄ²éѯ¡£
¼òµ¥µØËµ£¬ÊµÏÖ·½·¨ÈçÏÂËùʾ£º
SELECT¡¡ÁÐÃû£±£®£®£®ÁÐÃû£î¡¡from
(SELECT¡¡ÁÐ ......