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锘??xml version="1.0" encoding="utf-8" standalone="yes"?>亚洲美国产亚洲AV,亚洲国产成人久久77,久久夜色精品国产噜噜噜亚洲AVhttp://www.tkk7.com/mercurymarsx/articles/341154.html澶╂動嫻緺澶╂動嫻緺Mon, 20 Dec 2010 05:45:00 GMThttp://www.tkk7.com/mercurymarsx/articles/341154.htmlhttp://www.tkk7.com/mercurymarsx/comments/341154.htmlhttp://www.tkk7.com/mercurymarsx/articles/341154.html#Feedback0http://www.tkk7.com/mercurymarsx/comments/commentRss/341154.htmlhttp://www.tkk7.com/mercurymarsx/services/trackbacks/341154.html
鎬葷粨濡備笅錛?br /> 鎴戝垱寤轟簡涓€涓〃錛屾暟鎹涓嬶紝
SQL> select * from test;
       A1       A2
---------- ----------
      1       3
      2       4
      3       2
      3       5
      4       2
鐒跺悗鐢╮ank () over錛?br /> SQL> select a1,a2,rank () over (order by a1) rank from test;
       A1       A2    RANK
---------- ---------- ----------
      1       3       1
      2       4       2
      3       2       3
      3       5       3
      4       2       5
SQL> select a1,a2,rank () over (order by a2) rank from test;
       A1       A2    RANK
---------- ---------- ----------
      3       2       1
      4       2       1
      1       3       3
      2       4       4
      3       5       5
鍘熸潵榪欎釜灝辨槸鐢ㄦ潵鐪嬫帓鍚嶇殑涓滀笢鍟娿€?br /> 鎺ヤ笅鏉ョ湅鐪媟ow_number() over錛?br /> SQL> select a1,a2, row_number () over (order by a1) rank from test;
       A1       A2    RANK
---------- ---------- ----------
      1       3       1
      2       4       2
      3       2       3
      3       5       4
      4       2       5
SQL> select a1,a2, row_number () over (order by a2) rank from test;
       A1       A2    RANK
---------- ---------- ----------
      3       2       1
      4       2       2
      1       3       3
      2       4       4
      3       5       5
鍐嶇湅鐪媎ense_rank () over
SQL> select a1,a2, dense_rank () over (order by a1) rank from test;
       A1       A2    RANK
---------- ---------- ----------
      1       3       1
      2       4       2
      3       2       3
      3       5       3
      4       2       4
dense_rank鍦ㄦ湁鍑虹幇鐩稿悓鐨剅ank鍚庯紝rank鐨勫€兼槸绱ф帴涓婁竴嬈＄殑rank鍊箋€?br /> 鍙互榪欎箞鐞嗚В錛屾垜浠€氬父鎰忎箟涓婄殑top N 鐨勫疄鐜板簲璇ラ噰鐢╮ow_number() over 鑰屼笉鏄痳ank () over錛屽洜涓簉ow_number 鏄粰璁板綍鍔犱竴涓簭鍙鋒爣璁幫紝鑰宺ank 鏄浉褰撲簬榪涜鎺掑簭鍚庣殑鎺掑悕錛屼篃灝辨槸濡傛灉鎺掑簭鍒楁槸鐩稿悓鐨勶紝閭ｄ箞浠栦滑鐨勮繑鍥炲€間篃鏄浉鍚岀殑錛岃€宺ow_number鍒欎笉鍙兘榪斿洖鐩稿悓鍊箋€?br /> 鏀懼埌涓€璧風湅鐪嬪惂錛?br />
SQL>

select a1,a2,
2

rank () over (order by a1) rank,
3

dense_rank () over (order by a1) dense_rank,
4

row_number () over (order by a1) row_number
5

from test;

       A1       A2    RANK DENSE_RANK ROW_NUMBER
---------- ---------- ---------- ---------- ----------
      1       3       1       1       1
      2       4       2       2       2
      3       2       3       3       3
      3       5       3       3       4
      4       2       5       4       5
row_number()鍜宺ownum宸笉澶氾紝鍔熻兘鏇村己涓€鐐癸紙鍙互鍦ㄥ悇涓垎緇勫唴浠?寮€鏃舵帓搴忥級錛?br /> rank()鏄煩璺冩帓搴忥紝鏈変袱涓浜屽悕鏃舵帴涓嬫潵灝辨槸絎洓鍚嶏紙鍚屾牱鏄湪鍚勪釜鍒嗙粍鍐咃級錛?br /> dense_rank()l鏄繛緇帓搴忥紝鏈変袱涓浜屽悕鏃朵粛鐒惰窡鐫€絎笁鍚嶃€傜浉姣斾箣涓媟ow_number鏄病鏈夐噸澶嶅€肩殑錛?br />

澶╂動嫻緺 2010-12-20 13:45 鍙戣〃璇勮