1.ASCII 返回與指定的字元對應的十進位數; SQL> select ascii(A) A,ascii(a) a,ascii(0) zero,ascii( ) space from dual; A A ZERO SPACE 65 97 48 32 2. CHR 給出整數,返回對應的字元; SQL ...
1.ASCII 返回與指定的字元對應的十進位數; SQL> select ascii(A) A,ascii(a) a,ascii(0) zero,ascii( ) space from dual; A A ZERO SPACE --------- --------- --------- --------- 65 97 48 32 2. CHR 給出整數,返回對應的字元; SQL> select chr(54740) zhao,chr(65) chr65 from dual; ZH C -- - 趙 A 3. CONCAT 連接兩個字元串; SQL> select concat(010-,88888888)||轉23 高乾競電話 from dual; 高乾競電話 ---------------- 010-88888888轉23 4. INITCAP 返回字元串並將字元串的第一個字母變為大寫; SQL> select initcap(smith) upp from dual; UPP ----- Smith 5.INSTR(C1,C2,I,J) 在一個字元串中搜索指定的字元,返回發現指定的字元的位置; C1 被搜索的字元串 C2 希望搜索的字元串 I 搜索的開始位置,預設為1 J 出現的位置,預設為1 SQL> select instr(oracle traning,ra,1,2) instring from dual; INSTRING --------- 9 6.LENGTH 返回字元串的長度; SQL> select name,length(name),addr,length(addr),sal,length(to_char(sal)) from gao.nchar_tst; NAME LENGTH(NAME) ADDR LENGTH(ADDR) SAL LENGTH(TO_CHAR(SAL)) ------ ------------ ---------------- ------------ --------- -------------------- 高乾競 3 北京市海錠區 6 9999.99 7 7.LOWER 返回字元串,並將所有的字元小寫 SQL> select lower(AaBbCcDd)AaBbCcDd from dual; AABBCCDD -------- aabbccdd 8.UPPER 返回字元串,並將所有的字元大寫 SQL> select upper(AaBbCcDd) upper from dual; UPPER -------- AABBCCDD 9.RPAD和LPAD(粘貼字元) RPAD 在列的右邊粘貼字元 LPAD 在列的左邊粘貼字元 SQL> select lpad(rpad(gao,10,*),17,*)from dual; LPAD(RPAD(GAO,1 ----------------- *******gao******* 不夠字元則用*來填滿 10.LTRIM和RTRIM LTRIM 刪除左邊出現的字元串 RTRIM 刪除右邊出現的字元串 SQL> select ltrim(rtrim( gao qian jing , ), ) from dual; LTRIM(RTRIM( ------------- gao qian jing 11.SUBSTR(string,start,count) 取子字元串,從start開始,取count個 SQL> select substr(13088888888,3,8) from dual; SUBSTR( -------- 08888888 12.REPLACE(string,s1,s2) string 希望被替換的字元或變數 s1 被替換的字元串 s2 要替換的字元串 SQL> select replace(he love you,he,i) from dual; REPLACE(H ---------- i love you 13.SOUNDEX 返回一個與給定的字元串讀音相同的字元串 SQL> create table table1(xm varchar(8)); SQL> insert into table1 values(weather); SQL> insert into table1 values(wether); SQL> insert into table1 values(gao); SQL> select xm from table1 where soundex(xm)=soundex(weather); XM -------- weather wether • 14.TRIM(s from string) LEADING 剪掉前面的字元 TRAILING 剪掉後面的字元 如果不指定,預設為空格符 15.ABS 返回指定值的絕對值 SQL> select abs(100),abs(-100) from dual; ABS(100) ABS(-100) --------- --------- 100 100 16.ACOS 給出反餘弦的值 SQL> select acos(-1) from dual; ACOS(-1) --------- 3.1415927 17.ASIN 給出反正弦的值 SQL> select asin(0.5) from dual; ASIN(0.5) --------- .52359878 18.ATAN 返回一個數字的反正切值 SQL> select atan(1) from dual; ATAN(1) --------- .78539816 19.CEIL 返回大於或等於給出數字的最小整數 SQL> select ceil(3.1415927) from dual; CEIL(3.1415927) --------------- 4 20.COS 返回一個給定數字的餘弦 SQL> select cos(-3.1415927) from dual; COS(-3.1415927) --------------- -1 21.COSH 返回一個數字反餘弦值 SQL> select cosh(20) from dual; COSH(20) --------- 242582598 22.EXP 返回一個數字e的n次方根 SQL> select exp(2),exp(1) from dual; EXP(2) EXP(1) --------- --------- 7.3890561 2.7182818 23.FLOOR 對給定的數字取整數 SQL> select floor(2345.67) from dual; FLOOR(2345.67) -------------- 2345 24.LN 返回一個數字的對數值 SQL> select ln(1),ln(2),ln(2.7182818) from dual; LN(1) LN(2) LN(2.7182818) --------- --------- ------------- 0 .69314718 .99999999 25.LOG(n1,n2) 返回一個以n1為底n2的對數 SQL> select log(2,1),log(2,4) from dual; LOG(2,1) LOG(2,4) --------- --------- 0 2 26.MOD(n1,n2) 返回一個n1除以n2的餘數 SQL> select mod(10,3),mod(3,3),mod(2,3) from dual; MOD(10,3) MOD(3,3) MOD(2,3) --------- --------- --------- 1 0 2 27.POWER 返回n1的n2次方根 SQL> select power(2,10),power(3,3) from dual; POWER(2,10) POWER(3,3) ----------- ---------- 1024 27 28.ROUND和TRUNC 按照指定的精度進行舍入 SQL> select round(55.5),round(-55.4),trunc(55.5),trunc(-55.5) from dual; ROUND(55.5) ROUND(-55.4) TRUNC(55.5) TRUNC(-55.5) ----------- ------------ ----------- ------------ 56 -55 55 -55 29.SIGN 取數字n的符號,大於0返回1,小於0返回-1,等於0返回0 SQL> select sign(123),sign(-100),sign(0) from dual; SIGN(123) SIGN(-100) SIGN(0) --------- ---------- --------- 1 -1 0 30.SIN 返回一個數字的正弦值 SQL> select sin(1.57079) from dual; SIN(1.57079) ------------ 1 • 31.SIGH 返回雙曲正弦的值 SQL> select sin(20),sinh(20) from dual; SIN(20) SINH(20) --------- --------- .91294525 242582598 32.SQRT 返回數字n的根 SQL> select sqrt(64),sqrt(10) from dual; SQRT(64) SQRT(10) --------- --------- 8 3.1622777 33.TAN 返回數字的正切值 SQL> select tan(20),tan(10) from dual; TAN(20) TAN(10) --------- --------- 2.2371609 .64836083 34.TANH 返回數字n的雙曲正切值 SQL> select tanh(20),tan(20) from dual; TANH(20) TAN(20) --------- --------- 1 2.2371609 35.TRUNC 按照指定的精度截取一個數 SQL> select trunc(124.1666,-2) trunc1,trunc(124.16666,2) from dual; TRUNC1 TRUNC(124.16666,2) --------- ------------------ 100 124.16 36.ADD_MONTHS 增加或減去月份 SQL> select to_char(add_months(to_date(199912,yyyymm),2),yyyymm) from dual; TO_CHA ------ 200002 SQL> select to_char(add_months(to_date(199912,yyyymm),-2),yyyymm) from dual; TO_CHA ------ 199910 37.LAST_DAY 返回日期的最後一天 SQL> select to_char(sysdate,yyyy.mm.dd),to_char((sysdate)+1,yyyy.mm.dd) from dual; TO_CHAR(SY TO_CHAR((S ---------- ---------- 2004.05.09 2004.05.10 SQL> select last_day(sysdate) from dual; LAST_DAY(S ---------- 31-5月 -04 38.MONTHS_BETWEEN(date2,date1) 給出date2-date1的月份 SQL> select months_between(19-12月-1999,19-3月-1999) mon_between from dual; MON_BETWEEN ----------- 9 SQL>selectmonths_between(to_date(2000.05.20,yyyy.mm.dd),to_date(2005.05.20,yyyy.mm.dd)) mon_betw from dual; MON_BETW --------- -60 39.NEW_TIME(date,this,that) 給出在this時區=other時區的日期和時間 SQL> select to_char(sysdate,yyyy.mm.dd hh24:mi:ss) bj_time,to_char(new_time 2 (sysdate,PDT,GMT),yyyy.mm.dd hh24:mi:ss) los_angles from dual; BJ_TIME LOS_ANGLES ------------------- ------------------- 2004.05.09 11:05:32 2004.05.09 18:05:32 40.NEXT_DAY(date,day) 給出日期date和星期x之後計算下一個星期的日期 SQL> select next_day('18-5月-2001','星期五') next_day from dual; NEXT_DAY ---------- 25-5月 -01 41.SYSDATE 用來得到系統的當前日期 SQL> select to_char(sysdate,dd-mm-yyyy day) from dual; TO_CHAR(SYSDATE, ----------------- 09-05-2004 星期日 trunc(date,fmt)按照給出的要求將日期截斷,如果fmt=mi表示保留分,截斷秒 SQL> select to_char(trunc(sysdate,hh),yyyy.mm.dd hh24:mi:ss) hh, 2 to_char(trunc(sysdate,mi),yyyy.mm.dd hh24:mi:ss) hhmm from dual; HH HHMM ------------------- ------------------- 2004.05.09 11:00:00 2004.05.09 11:17:00 42.CHARTOROWID 將字元數據類型轉換為ROWID類型 SQL> select rowid,rowidtochar(rowid),ename from scott.emp; ROWID ROWIDTOCHAR(ROWID) ENAME ------------------ ------------------ ---------- AAAAfKAACAAAAEqAAA AAAAfKAACAAAAEqAAA SMITH AAAAfKAACAAAAEqAAB AAAAfKAACAAAAEqAAB ALLEN AAAAfKAACAAAAEqAAC AAAAfKAACAAAAEqAAC WARD AAAAfKAACAAAAEqAAD AAAAfKAACAAAAEqAAD JONES 43.CONVERT(c,dset,sset) 將源字元串 sset從一個語言字元集轉換到另一個目的dset字元集 SQL> select convert(strutz,we8hp,f7dec) "conversion" from dual; conver ------ strutz 44.HEXTORAW 將一個十六進位構成的字元串轉換為二進位 45.RAWTOHEXT 將一個二進位構成的字元串轉換為十六進位 46.ROWIDTOCHAR 將ROWID數據類型轉換為字元類型 47.TO_CHAR(date,format) SQL> select to_char(sysdate,yyyy/mm/dd hh24:mi:ss) from dual; TO_CHAR(SYSDATE,YY ------------------- 2004/05/09 21:14:41 • 48.TO_DATE(string,format) 將字元串轉化為ORACLE中的一個日期 49.TO_MULTI_BYTE 將字元串中的單位元組字元轉化為多位元組字元 SQL> select to_multi_byte(高) from dual; TO -- 高 50.TO_NUMBER 將給出的字元轉換為數字 SQL> select to_number(1999) year from dual; YEAR --------- 1999 51.BFILENAME(dir,file) 指定一個外部二進位文件 SQL>insert into file_tb1 values(bfilename(lob_dir1,image1.gif)); 52.CONVERT(x,desc,source) 將x欄位或變數的源source轉換為desc SQL> select sid,serial#,username,decode(command, 2 0,none, 3 2,insert, 4 3, 5 select, 6 6,update, 7 7,delete, 8 8,drop, 9 other) cmd from v$session where type!=background; SID SERIAL# USERNAME CMD --------- --------- ------------------------------ ------ 1 1 none 2 1 none 3 1 none 4 1 none 5 1 none 6 1 none 7 1275 none 8 1275 none 9 20 GAO select 10 40 GAO none 53.DUMP(s,fmt,start,length) DUMP函數以fmt指定的內部數字格式返回一個VARCHAR2類型的值 SQL> col global_name for a30 SQL> col dump_string for a50 SQL> set lin 200 SQL> select global_name,dump(global_name,1017,8,5) dump_string from global_name; GLOBAL_NAME DUMP_STRING ------------------------------ -------------------------------------------------- ORACLE.WORLD Typ=1 Len=12 CharacterSet=ZHS16GBK: W,O,R,L,D 54.EMPTY_BLOB()和EMPTY_CLOB() 這兩個函數都是用來對大數據類型欄位進行初始化操作的函數 55.GREATEST 返回一組表達式中的最大值,即比較字元的編碼大小. SQL> select greatest(AA,AB,AC) from dual; GR -- AC SQL> select greatest(啊,安,天) from dual; GR -- 天 56.LEAST 返回一組表達式中的最小值 SQL> select least(啊,安,天) from dual; LE -- 啊 57.UID 返回標識當前用戶的唯一整數 SQL> show user USER 為"GAO" SQL> select username,user_id from dba_users where user_id=uid; USERNAME USER_ID ------------------------------ --------- GAO 25 58.USER 返回當前用戶的名字 SQL> select user from dual; USER ------------------------------ GAO 59.USEREVN 返回當前用戶環境的信息,opt可以是: ENTRYID,SESSIONID,TERMINAL,ISDBA,LABLE,LANGUAGE,CLIENT_INFO,LANG,VSIZE ISDBA 查看當前用戶是否是DBA如果是則返回true SQL> select userenv(isdba) from dual; USEREN ------ FALSE SQL> select userenv(isdba) from dual; USEREN ------ TRUE SESSION 返回會話標誌 SQL> select userenv(sessionid) from dual; USERENV(SESSIONID) -------------------- 152 ENTRYID 返回會話人口標誌 SQL> select userenv(entryid) from dual; USERENV(ENTRYID) ------------------ 0 INSTANCE 返回當前INSTANCE的標誌 SQL> select userenv(instance) from dual; USERENV(INSTANCE) ------------------- 1 LANGUAGE 返回當前環境變數 SQL> select userenv(language) from dual; USERENV(LANGUAGE) ---------------------------------------------------- SIMPLIFIED CHINESE_CHINA.ZHS16GBK LANG 返回當前環境的語言的縮寫 SQL> select userenv(lang) from dual; USERENV(LANG) ---------------------------------------------------- ZHS TERMINAL 返回用戶的終端或機器的標誌 SQL> select userenv(terminal) from dual; USERENV(TERMINA ---------------- GAO VSIZE(X) 返回X的大小(位元組)數 SQL> select vsize(user),user from dual; VSIZE(USER) USER ----------- ------------------------------ 6 SYSTEM • 60.AVG(DISTINCT|ALL) all表示對所有的值求平均值,distinct只對不同的值求平均值 SQLWKS> create table table3(xm varchar(8),sal number(7,2)); 語句已處理。 SQLWKS> insert into table3 values(gao,1111.11); SQLWKS> insert into table3 values(gao,1111.11); SQLWKS> insert into table3 values(zhu,5555.55); SQLWKS> commit; SQL> select avg(distinct sal) from gao.table3; AVG(DISTINCTSAL) ---------------- 3333.33 SQL> select avg(all sal) from gao.table3; AVG(ALLSAL) ----------- 2592.59 61.MAX(DISTINCT|ALL) 求最大值,ALL表示對所有的值求最大值,DISTINCT表示對不同的值求最大值,相同的只取一次 SQL> select max(distinct sal) from scott.emp; MAX(DISTINCTSAL) ---------------- 5000 62.MIN(DISTINCT|ALL) 求最小值,ALL表示對所有的值求最小值,DISTINCT表示對不同的值求最小值,相同的只取一次 SQL> select min(all sal) from gao.table3; MIN(ALLSAL) ----------- 1111.11 63.STDDEV(distinct|all) 求標準差,ALL表示對所有的值求標準差,DISTINCT表示只對不同的值求標準差 SQL> select stddev(sal) from scott.emp; STDDEV(SAL) ----------- 1182.5032 SQL> select stddev(distinct sal) from scott.emp; STDDEV(DISTINCTSAL) ------------------- 1229.951 64.VARIANCE(DISTINCT|ALL) 求協方差 SQL> select variance(sal) from scott.emp; VARIANCE(SAL) ------------- 1398313.9 65.GROUP BY 主要用來對一組數進行統計 SQL> select deptno,count(*),sum(sal) from scott.emp group by deptno; DEPTNO COUNT(*) SUM(SAL) --------- --------- --------- 10 3 8750 20 5 10875 30 6 9400 66.HAVING 對分組統計再加限制條件 SQL> select deptno,count(*),sum(sal) from scott.emp group by deptno having count(*)>=5; DEPTNO COUNT(*) SUM(SAL) --------- --------- --------- 20 5 10875 30 6 9400 SQL> select deptno,count(*),sum(sal) from scott.emp having count(*)>=5 group by deptno ; DEPTNO COUNT(*) SUM(SAL) --------- --------- --------- 20 5 10875 30 6 9400 67.ORDER BY 用於對查詢到的結果進行排序輸出 SQL> select deptno,ename,sal from scott.emp order by deptno,sal desc; DEPTNO ENAME SAL --------- ---------- --------- 10 KING 5000 10 CLARK 2450 10 MILLER 1300 20 SCOTT 3000 20 FORD 3000 20 JONES 2975 20 ADAMS 1100 20 SMITH 800 30 BLAKE 2850 30 ALLEN 1600 30 TURNER 1500 30 WARD 1250 30 MARTIN 1250 30 JAMES 950 68. pl/sql中的case語句 select (case when DUMMY='X' then 0 else 1 end) as flag from dual; case的第1種用法: case col when 'a' then 1 when 'b' then 2 else 0 end 這種用法跟decode一樣沒什麼區別 case的第2種用法: case when score <60 then 'd' when score >=60 and score <70 then 'c' when score >=70 and score <80 then 'b' else 'a' end 69.NVL(expr1, expr2) NVL(expr1, expr2)->expr1為NULL,返回expr2;不為NULL,返回expr1。註意兩者的類型要一致 NVL2 (expr1, expr2, expr3) ->expr1不為NULL,返回expr2;為NULL,返回expr3。expr2和expr3類型不同的話,expr3會轉換為expr2的類型 NULLIF (expr1, expr2) ->相等返回NULL,不等返回expr1 • Oracle分析函數參考手冊 ============================================= 作者: xsb([url]http://xsb.itpub.net)[/url] 發表於:2006.03.01 12:22 分類: DW&BI 出處:http://xsb.itpub.net/post/419/33028 --------------------------------------------------------------- Oracle從8.1.6開始提供分析函數,分析函數用於計算基於組的某種聚合值,它和聚合函數的不同之處是對於每個組返回多行, 而聚合函數對於每個組只返回一行。 常用的分析函數如下所列: row_number() over(partition by ... order by ...) rank() over(partition by ... order by ...) dense_rank() over(partition by ... order by ...) count() over(partition by ... order by ...) max() over(partition by ... order by ...) min() over(partition by ... order by ...) sum() over(partition by ... order by ...) avg() over(partition by ... order by ...) first_value() over(partition by ... order by ...) last_value() over(partition by ... order by ...) lag() over(partition by ... order by ...) lead() over(partition by ... order by ...) 下麵例子中使用的表來自Oracle自帶的HR用戶下的表,如果沒有安裝該用戶,可以在SYS用戶下運行 $ORACLE_HOME/demo/schema/human_resources/hr_main.sql來創建。 除本文內容外,你還可參考: ROLLUP與CUBE [url]http://xsb.itpub.net/post/419/29159[/url] 分析函數使用例子介紹:[url]http://xsb.itpub.net/post/419/44634[/url] 本文如果未指明,預設是在HR用戶下運行例子。 開窗函數的的理解: 開窗函數指定了分析函數工作的數據視窗大小,這個數據視窗大小可能會隨著行的變化而變化,舉例如下: over(order by salary) 按照salary排序進行累計,order by是個預設的開窗函數 over(partition by deptno)按照部門分區 over(order by salary range between 50 preceding and 150 following) 每行對應的數據視窗是之前行幅度值不超過50,之後行幅度值不超過150 over(order by salary rows between 50 preceding and 150 following) 每行對應的數據視窗是之前50行,之後150行 over(order by salary rows between unbounded preceding and unbounded following) 每行對應的數據視窗是從第一行到最後一行,等效: over(order by salary range between unbounded preceding and unbounded following) 主要參考資料:《expert one-on-one》 Tom Kyte 《Oracle9i SQL Reference》第6章 ohwww 2007-3-12 09:19 70。AVG 功能描述:用於計算一個組和數據視窗內表達式的平均值。 SAMPLE:下麵的例子中列c_mavg計算員工表中每個員工的平均薪水報告,該平均值由當前員工和與之具有相同經理的前一個和後一個三者的平均數得來; SELECT manager_id, last_name, hire_date, salary, AVG(salary) OVER (PARTITION BY manager_id ORDER BY hire_date ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING) AS c_mavg FROM employees; MANAGER_ID LAST_NAME HIRE_DATE SALARY C_MAVG ---------- ------------------------- --------- ---------- ---------- 100 Kochhar 21-SEP-89 17000 17000 100 De Haan 13-JAN-93 17000 15000 100 Raphaely 07-DEC-94 11000 11966.6667 100 Kaufling 01-MAY-95 7900 10633.3333 100 Hartstein 17-FEB-96 13000 9633.33333 100 Weiss 18-JUL-96 8000 11666.6667 100 Russell 01-OCT-96 14000 11833.3333 71。CORR 功能描述:返回一對錶達式的相關係數,它是如下的縮寫: COVAR_POP(expr1,expr2)/STDDEV_POP(expr1)*STDDEV_POP(expr2)) 從統計上講,相關性是變數之間關聯的強度,變數之間的關聯意味著在某種程度 上一個變數的值可由其它的值進行預測。通過返回一個-1~1之間的一個數, 相關 繫數給出了關聯的強度,0表示不相關。 SAMPLE:下例返回1998年月銷售收入和月單位銷售的關係的累積繫數(本例在SH用戶下運行) SELECT t.calendar_month_number, CORR (SUM(s.amount_sold), SUM(s.quantity_sold)) OVER (ORDER BY t.calendar_month_number) as CUM_CORR FROM sales s, times t WHERE s.time_id = t.time_id AND calendar_year = 1998 GROUP BY t.calendar_month_number ORDER BY t.calendar_month_number; CALENDAR_MONTH_NUMBER CUM_CORR --------------------- ---------- 1 2 1 3 .994309382 4 .852040875 5 .846652204 6 .871250628 7 .910029803 8 .917556399 9 .920154356 10 .86720251 11 .844864765 12 .903542662 72。COVAR_POP 功能描述:返回一對錶達式的總體協方差。 SAMPLE:下例CUM_COVP返回定價和最小產品價格的累積總體協方差 SELECT product_id, supplier_id, COVAR_POP(list_price, min_price) OVER (ORDER BY product_id, supplier_id) AS CUM_COVP, COVAR_SAMP(list_price, min_price) OVER (ORDER BY product_id, supplier_id) AS CUM_COVS FROM product_information p WHERE category_id = 29 ORDER BY product_id, supplier_id; PRODUCT_ID SUPPLIER_ID CUM_COVP CUM_COVS ---------- ----------- ---------- ---------- 1774 103088 0 1775 103087 1473.25 2946.5 1794 103096 1702.77778 2554.16667 1825 103093 1926.25 2568.33333 2004 103086 1591.4 1989.25 2005 103086 1512.5 1815 2416 103088 1475.97959 1721.97619 . . 73。COVAR_SAMP 功能描述:返回一對錶達式的樣本協方差 SAMPLE:下例CUM_COVS返回定價和最小產品價格的累積樣本協方差 SELECT product_id, supplier_id, COVAR_POP(list_price, min_price) OVER (ORDER BY product_id, supplier_id) AS CUM_COVP, COVAR_SAMP(list_price, min_price) OVER (ORDER BY product_id, supplier_id) AS CUM_COVS FROM product_information p WHERE category_id = 29 ORDER BY product_id, supplier_id; PRODUCT_ID SUPPLIER_ID CUM_COVP CUM_COVS ---------- ----------- ---------- ---------- 1774 103088 0 1775 103087 1473.25 2946.5 1794 103096 1702.77778 2554.16667 1825 103093 1926.25 2568.33333 2004 103086 1591.4 1989.25 2005 103086 1512.5 1815 2416 103088 1475.97959 1721.97619 • 74。COUNT 功能描述:對一組內發生的事情進行累積計數,如果指定*或一些非空常數,count將對所有行計數,如果指定一個表達式,count 返回表達式非空賦值的計數,當有相同值出現時,這些相等的值都會被納入被計算的值;可以使用DISTINCT來記錄去掉一組中完全 相同的數據後出現的行數。 SAMPLE:下麵例子中計算每個員工在按薪水排序中當前行附近薪水在[n-50,n+150]之間的行數,n表示當前行的薪水 例如,Philtanker的薪水2200,排在他之前的行中薪水大於等於2200-50的有1行,排在他之後的行中薪水小於等於2200+150的行 沒有,所以count計數值cnt3為2(包括自己當前行);cnt2值相當於小於等於當前行的SALARY值的所有行數 SELECT last_name, salary, COUNT(*) OVER () AS cnt1, COUNT(*) OVER (ORDER BY salary) AS cnt2, COUNT(*) OVER (ORDER BY salary RANGE BETWEEN 50 PRECEDING AND 150 FOLLOWING) AS cnt3 FROM employees; LAST_NAME SALARY CNT1 CNT2 CNT3 ------------------------- ---------- ---------- ---------- ---------- Olson 2100 107 1 3 Markle 2200 107 3 2 Philtanker 2200 107 3 2 Landry 2400 107 5 8 Gee 2400 107 5 8 Colmenares 2500 107 11 10 Patel 2500 107 11 10 . . 75。CUME_DIST 功能描述:計算一行在組中的相對位置,CUME_DIST總是返回大於0、小於或等於1的數,該數表示該行在N行中的位置。例如, 在一個3行的組中,返回的累計分佈值為1/3、2/3、3/3 SAMPLE:下例中計算每個工種的員工按薪水排序依次累積出現的分佈百分比 SELECT job_id, last_name, salary, CUME_DIST() OVER (PARTITION BY job_id ORDER BY salary) AS cume_dist FROM employees WHERE job_id LIKE 'PU%'; JOB_ID LAST_NAME SALARY CUME_DIST ---------- ------------------------- ---------- ---------- PU_CLERK Colmenares 2500 .2 PU_CLERK Himuro 2600 .4 PU_CLERK Tobias 2800 .6 PU_CLERK Baida 2900 .8 PU_CLERK Khoo 3100 1 PU_MAN Raphaely 11000 1 76。DENSE_RANK 功能描述:根據ORDER BY子句中表達式的值,從查詢返回的每一行,計算它們與其它行的相對位置。組內的數據按ORDER BY子句排序,然後給每一行賦一個號,從而形成一個序列,該序列從1開始,往後累加。每次ORDER BY表達式的值發生變化時,該序列也隨之增加。有同樣值的行得到同樣的數字序號(認為null時相等的)。密集的序列返回的時沒有間隔的數 SAMPLE:下例中計算每個員工按部門分區再按薪水排序,依次出現的序列號(註意與RANK函數的區別) SELECT d.department_id , e.last_name, e.salary, DENSE_RANK() OVER (PARTITION BY e.department_id ORDER BY e.salary) as drank FROM employees e, departments d WHERE e.department_id = d.department_id AND d.department_id IN ('60', '90'); DEPARTMENT_ID LAST_NAME SALARY DRANK ------------- ------------------------- ---------- ---------- 60 Lorentz 4200 1 60 Austin 4800 2 60 Pataballa 4800 2 60 Ernst 6000 3 60 Hunold 9000 4 90 Kochhar 17000 1 90 De Haan 17000 1 90 King 24000 2 77。FIRST 功能描述:從DENSE_RANK返回的集合中取出排在最前面的一個值的行(可能多行,因為值可能相等),因此完整的語法需要在開始處加上一個集合函數以從中取出記錄 SAMPLE:下麵例子中DENSE_RANK按部門分區,再按佣金commission_pct排序,FIRST取出佣金最低的對應的所有行,然後前面的MAX函數從這個集合中取出薪水最低的值;LAST取出佣金最高的對應的所有行,然後前面的MIN函數從這個集合中取出薪水最高的值 SELECT last_name, department_id, salary, MIN(salary) KEEP (DENSE_RANK FIRST ORDER BY commission_pct) OVER (PARTITION BY department_id) "Worst", MAX(salary) KEEP (DENSE_RANK LAST ORDER BY commission_pct) OVER (PARTITION BY department_id) "Best" FROM employees WHERE department_id in (20,80) ORDER BY department_id, salary; LAST_NAME DEPARTMENT_ID SALARY Worst Best ------------------------- ------------- ---------- ---------- ---------- Fay 20 6000 6000 13000 Hartstein 20 13000 6000 13000 Kumar 80 6100 6100 14000 Banda 80 6200 6100 14000 Johnson 80 6200 6100 14000 Ande 80 6400 6100 14000 Lee 80 6800 6100 14000 Tuvault 80 7000 6100 14000 Sewall 80 7000 6100 14000 Marvins 80 7200 6100 14000 Bates 80 7300 6100 14000 . . . 78。FIRST_VALUE 功能描述:返回組中數據視窗的第一個值。 SAMPLE:下麵例子計算按部門分區按薪水排序的數據視窗的第一個值對應的名字,如果薪水的第一個值有多個,則從多個對應的名字中取預設排序的第一個名字 SELECT department_id, last_name, salary, FIRST_VALUE(last_name) OVER (PARTITION BY department_id ORDER BY salary ASC ) AS lowest_sal FROM employees WHERE department_id in(20,30); DEPARTMENT_ID LAST_NAME SALARY LOWEST_SAL ------------- ------------------------- ---------- -------------- 20 Fay 6000 Fay 20 Hartstein 13000 Fay 30 Colmenares 2500 Colmenares 30 Himuro 2600 Colmenares 30 Tobias 2800 Colmenares 30 Baida 2900 Colmenares 30 Khoo 3100 Colmenares 30 Raphaely 11000 Colmenares 79。LAG 功能描述:可以訪問結果集中的其它行而不用進行自連接。它允許去處理游標,就好像游標是一個數組一樣。在給定組中可參考當前行之前的行,這樣就可以從組中與當前行一起選擇以前的行。Offset是一個正整數,其預設值為1,若索引超出視窗的範圍,就返回預設值(預設返回的是組中第一行),其相反的函數是LEAD SAMPLE:下麵的例子中列prev_sal返回按hire_date排序的前1行的salary值 SELECT last_name, hire_date, salary, LAG(salary, 1, 0) OVER (ORDER BY hire_date) AS prev_sal FROM employees WHERE job_id = 'PU_CLERK'; LAST_NAME HIRE_DATE SALARY PREV_SAL ------------------------- ---------- ---------- ---------- Khoo 18-5月 -95 3100 0 Tobias 24-7月 -97 2800 3100 Baida 24-12月-97 2900 2800 Himuro 15-11月-98 2600 2900 Colmenares 10-8月 -99 2500 2600 80。LAST 功能描述:從DENSE_RANK返回的集合中取出排在最後面的一個值的行(可能多行,因為值可能相等),因此完整的語法需要在開始處加上一個集合函數以從中取出記錄 SAMPLE:下麵例子中DENSE_RANK按部門分區,再按佣金commission_pct排序,FIRST取出佣金最低的對應的所有行,然後前面的MAX函數從這個集合中取出薪水最低的值;LAST取出佣金最高的對應的所有行,然後前面的MIN函數從這個集合中取出薪水最高的值 SELECT last_name, department_id, salary, MIN(salary) KEEP (DENSE_RANK FIRST ORDER BY commission_pct) OVER (PARTITION BY department_id) "Worst", MAX(salary) KEEP (DENSE_RANK LAST ORDER BY commission_pct) OVER (PARTITION BY department_id) "Best" FROM employees WHERE department_id in (20,80) ORDER BY department_id, salary; LAST_NAME DEPARTMENT_ID SALARY Worst Best ------------------------- ------------- ---------- ---------- ---------- Fay 20 6000 6000 13000 Hartstein 20 13000 6000 13000 Kumar 80 6100 6100 14000 Banda 80 6200 6100 14000 Johnson 80 6200 6100 14000 Ande 80 6400 6100 14000 Lee 80 6800 6100 14000 Tuvault 80 7000 6100 14000 Sewall 80 7000 6100 14000 Marvins 80 7200 6100 14000 Bates 80 7300 6100 14000 . 81。LAST_VALUE 功能描述:返回組中數據視窗的最後一個值。 SAMPLE:下麵例子計算按部門分區按薪水排序的數據視窗的最後一個值對應的名字,如果薪水的最後一個值有多個,則從多個對應的名字中取預設排序的最後一個名字 SELECT department_id, last_name, salary, LAST_VALUE(last_name) OVER(PARTITION BY department_id ORDER BY salary) AS highest_sal FROM employees WHERE department_id in(20,30); DEPARTMENT_ID LAST_NAME SALARY HIGHEST_SAL ------------- ------------------------- ---------- ------------ 20 Fay 6000 Fay 20 Hartstein 13000 Hartstein 30 Colmenares 2500 Colmenares 30 Himuro 2600 Himuro 30 Tobias 2800 Tobias 30 Baida 2900 Baida 30 Khoo 3100 Khoo 30 Raphaely 11000 Raphaely 82。LEAD 功能描述:LEAD與LAG相反,LEAD可以訪問組中當前行之後的行。Offset是一個正整數,其預設值為1,若索引超出視窗的範圍,就返回預設值(預設返回的是組中第一行) SAMPLE:下麵的例子中每行的"NextHired"返回按hire_date排序的下一行的hire_date值 SELECT last_name, hire_date, LEAD(hire_date, 1) OVER (ORDER BY hire_date) AS "NextHired" FROM employees WHERE department_id = 30; LAST_NAME HIRE_DATE NextHired ------------------------- --------- --------- Raphaely 07-DEC-94 18-MAY-95 Khoo 18-MAY-95 24-JUL-97 Tobias 24-JUL-97 24-DEC-97 Baida 24-DEC-97 15-NOV-98 Himuro 15-NOV-98 10-AUG-99 Colmenares 10-AUG-99 83。MAX 功能描述:在一個組中的數據視窗中查找表達式的最大值。 SAMPLE:下麵例子中dept_max返回當前行所在部門的最大薪水值 SELECT department_id, last_name, salary, MAX(salary) OVER (PARTITION BY department_id) AS dept_max FROM employees WHERE department_id in (10,20,30); DEPARTMENT_ID LAST_NAME SALARY DEPT_MAX ------------- ------------------------- ---------- ---------- 10 Whalen 4400 4400 20 Hartstein 13000 13000 20 Fay 6000 13000 30 Raphaely 11000 11000 30 Khoo 3100 11000 30 Baida 2900 11000 30 Tobias 2800 11000 30 Himuro 2600 11000 30 Colmenares 2500 11000 84。MIN 功能描述:在一個組中的數據視窗中查找表達式的最小值。 SAMPLE:下麵例子中dept_min返回當前行所在部門的最小薪水值 SELECT department_id, last_name, salary, MIN(salary) OVER (PARTITION BY department_id) AS dept_min FROM employees WHERE department_id in (10,20,30); DEPARTMENT_ID LAST_NAME SALARY DEPT_MIN ------------- ------------------------- ---------- ---------- 10 Whalen 4400 4400 20 Hartstein 13000 6000 20 Fay 6000 6000 30 Raphaely 11000 2500 30 Khoo 3100 2500 30 Baida 2900 2500 30 Tobias 2800 2500 30 Himuro 2600 2500 30 Colmenares 2500 2500 85。NTILE 功能描述:將一個組分為"表達式"的散列表示,例如,如果表達式=4,則給組中的每一行分配一個數(從1到4),如果組中有20行,則給前5行分配1,給下5行分配2等等。如果組的基數不能由表達式值平均分開,則對這些行進行分配時,組中就沒有任何percentile的行數比其它percentile的行數超過一行,最低的percentile是那些擁有額外行的percentile。例如,若表達式=4,行數=21,則percentile=1的有5行,percentile=2的有5行等等。 SAMPLE:下例中把6行數據分為4份 SELECT last_name, salary, NTILE(4) OVER (ORDER BY salary DESC) AS quartile FROM employees WHERE department_id = 100; LAST_NAME SALARY QUARTILE ------------------------- ---------- ---------- Greenberg 12000 1 Faviet 9000 1 Chen 8200 2 Urman 7800 2 Sciarra 7700 3 Popp 6900 4 86。PERCENT_RANK 功能描述:和CUME_DIST(累積分配)函數類似,對於一個組中給定的行來說,在計算那行的序號時,先減1,然後除以n-1(n為組中所有的行數)。該函數總是返回0~1(包括1)之間的數。 SAMPLE:下例中如果Khoo的salary為2900,則pr值為0.6,因為RANK函數對於等值的返回序列值是一樣的 SELECT department_id, last_name, salary, PERCENT_RANK() OVER (PARTITION BY department_id ORDER BY salary) AS pr FROM employees WHERE department_id < 50 ORDER BY department_id,salary; DEPARTMENT_ID LAST_NAME SALARY PR ------------- ------------------------- ---------- ---------- 10 Whalen 4400 0 20 Fay 6000 0 20 Hartstein 13000 1 30 Colmenares 2500 0 30 Himuro 2600 0.2 30 Tobias 2800 0.4 30 Baida 2900 0.6 30 Khoo 3100 0.8 30 Raphaely 11000 1 40 Mavris 6500 0 • 87。PERCENTILE_CONT 功能描述:返回一個與輸入的分佈百分比值相對應的數據值,分佈百分比的計算方法見函數PERCENT_RANK,如果沒有正好對應的數據值,就通過下麵演算法來得到值: RN = 1+ (P*(N-1)) 其中P是輸入的分佈百分比值,N是組內的行數 CRN = CEIL(RN) FRN = FLOOR(RN) if (CRN = FRN = RN) then (value of expression from row at RN) else (CRN - RN) * (value of expression for row at FRN) + (RN - FRN) * (value of expression for row at CRN) 註意:本函數與PERCENTILE_DISC的區別在找不到對應的分佈值時返回的替代值的計算方法不同 SAMPLE:在下例中,對於部門60的Percentile_Cont值計算如下: P=0.7 N=5 RN =1+ (P*(N-1)=1+(0.7*(5-1))=3.8 CRN = CEIL(3.8)=4 FRN = FLOOR(3.8)=3 (4 - 3.8)* 4800 + (3.8 - 3) * 6000 = 5760 SELECT last_name, salary, department_id, PERCENTILE_CONT(0.7) WITHIN GROUP (ORDER BY salary) OVER (PARTITION BY department_id) "Percentile_Cont", PERCENT_RANK() OVER (PARTITION BY department_id ORDER BY salary) "Percent_Rank" FROM employees WHERE department_id IN (30, 60); LAST_NAME SALARY DEPARTMENT_ID Percentile_Cont Percent_Rank ------------------------- ---------- ------------- --------------- ------------ Colmenares 2500 30 3000 0 Himuro 2600 30 3000 0.2 Tobias 2800 30 3000 0.4 Baida 2900 30 3000 0.6 Khoo 3100 30 3000 0.8 Raphaely 11000 30 3000 1 Lorentz 4200 60 5760 0 Austin 4800 60 5760 0.25 Pataballa 4800 60 5760 0.25 Ernst 6000 60 5760 0.75 Hunold 9000 60 5760 1 88。PERCENTILE_DISC 功能描述:返回一個與輸入的分佈百分比值相對應的數據值,分佈百分比的計算方法見函數CUME_DIST,如果沒有正好對應的數據值,就取大於該分佈值的下一個值。 註意:本函數與PERCENTILE_CONT的區別在找不到對應的分佈值時返回的替代值的計算方法不同 SAMPLE:下例中0.7的分佈值在部門30中沒有對應的Cume_Dist值,所以就取下一個分佈值0.83333333所對應的SALARY來替代 SELECT last_name, salary, department_id, PERCENTILE_DISC(0.7) WITHIN GROUP (ORDER BY salary ) OVER (PARTITION BY department_id) "Percentile_Disc", CUME_DIST() OVER (PARTITION BY department_id ORDER BY salary) "Cume_Dist" FROM employees WHERE department_id in (30, 60); LAST_NAME SALARY DEPARTMENT_ID Percentile_Disc Cume_Dist ------------------------- ---------- ------------- --------------- ---------- Colmenares 2500 30 3100 .166666667 Himuro 2600 30 3100 .333333333 Tobias 2800 30 3100 .5 Baida 2900 30 3100 .666666667 Khoo 3100 30 3100 .833333333 Raphaely 11000 30 3100 1 Lorentz 4200 60 6000 .2 Austin 4800 60 6000 .6 Pataballa 4800 60 6000 .6 Ernst 6000 60 6000 .8 Hunold 9000 60 6000 1 89。RANK 功能描述:根據ORDER BY子句中表達式的值,從查詢返回的每一行,計算它們與其它行的相對位置。組內的數據按ORDER BY子句排序, 然後給每一行賦一個號,從而形成一個序列,該序列從1開始,往後累加。每次ORDER BY表達式的值發生變化時,該序列也隨之增加。 有同樣值的行得到同樣的數字序號(認為null時相等的)。然而,如果兩行的確得到同樣的排序,則序數將隨後跳躍。若兩行序數為1, 則沒有序數2,序列將給組中的下一行分配值3,DENSE_RANK則沒有任何跳躍。 SAMPLE:下例中計算每個員工按部門分區再按薪水排序,依次出現的序列號(註意與DENSE_RANK函數的區別) SELECT d.department_id , e.last_name, e.salary, RANK() OVER (PARTITION BY e.department_id ORDER BY e.salary) as drank FROM employees e, departments d WHERE e.department_id = d.department_id AND d.department_id IN ('60', '90'); DEPARTMENT_ID LAST_NAME SALARY DRANK ------------- ------------------------- ---------- ---------- 60 Lorentz 4200 1 60 Austin 4800 2 60 Pataballa 4800 2 60 Ernst 6000 4 60 Hunold 9000 5 90 Kochhar 17000 1 90 De Haan 17000 1 90 King 24000 3 90。RATIO_TO_REPORT 功能描述:該函數計算expression/(sum(expression))的值,它給出相對於總數的百分比,即當前行對sum(expression)的貢獻。 SAMPLE:下例計算每個員工的工資占該類員工總工資的百分比 SELECT last_name, salary, RATIO_TO_REPORT(salary) OVER () AS rr FROM employees WHERE job_id = 'PU_CLERK'; LAST_NAME SALARY RR ------------------------- ---------- ---------- Khoo 3100 .223021583 Baida 2900 .208633094 Tobias 2800 .201438849 Himuro 2600 .18705036 Colmenares 2500 .179856115 • 91。REGR_ (Linear Regression) Functions 功能描述:這些線性回歸函數適合最小二乘法回歸線,有9個不同的回歸函數可使用。 REGR_SLOPE:返回斜率,等於COVAR_POP(expr1, expr2) / VAR_POP(expr2) REGR_INTERCEPT:返回回歸線的y截距,等於 AVG(expr1) - REGR_SLOPE(expr1, expr2) * AVG(expr2) REGR_COUNT:返回用於填充回歸線的非空數字對的數目 REGR_R2:返回回歸線的決定繫數,計算式為: If VAR_POP(expr2) = 0 then return NULL If VAR_POP(expr1) = 0 and VAR_POP(expr2) != 0 then return 1 If VAR_POP(expr1) > 0 and VAR_POP(expr2 != 0 then return POWER(CORR(expr1,expr),2) REGR_AVGX:計算回歸線的自變數(expr2)的平均值,去掉了空對(expr1, expr2)後,等於AVG(expr2) REGR_AVGY:計算回歸線的應變數(expr1)的平均值,去掉了空對(expr1, expr2)後,等於AVG(expr1) REGR_SXX: 返回值等於REGR_COUNT(expr1, expr2) * VAR_POP(expr2) REGR_SYY: 返回值等於REGR_COUNT(expr1, expr2) * VAR_POP(expr1) REGR_SXY: 返回值等於REGR_COUNT(expr1, expr2) * COVAR_POP(expr1, expr2) (下麵的例子都是在SH用戶下完成的) SAMPLE 1:下例計算1998年最後三個星期中兩種產品(260和270)在周末的銷售量中已開發票數量和總數量的累積斜率和回歸線的截距 SELECT t.fiscal_month_number "Month", t.day_number_in_month "Day", REGR_SLOPE(s.amount_sold, s.quantity_sold) OVER (ORDER BY t.fiscal_month_desc, t.day_number_in_month) AS CUM_SLOPE, REGR_INTERCEPT(s.amount_sold, s.quantity_sold) OVER (ORDER BY t.fiscal_month_desc, t.day_number_in_month) AS CUM_ICPT FROM sales s, times t WHERE s.time_id = t.time_id AND s.prod_id IN (270, 260) AND t.fiscal_year=1998 AND t.fiscal_week_number IN (50, 51, 52) AND t.day_number_in_week IN (6,7) ORDER BY t.fiscal_month_desc, t.day_number_in_month; Month Day CUM_SLOPE CUM_ICPT ---------- ---------- ---------- ---------- 12 12 -68 1872 12 12 -68 1872 12 13 -20.244898 1254.36735 12 13 -20.244898 1254.36735 12 19 -18.826087 1287 12 20 62.4561404 125.28655 12 20 62.4561404 125.28655 12 20 62.4561404 125.28655 12 20 62.4561404 125.28655 12 26 67.2658228 58.9712313 12 26 67.2658228 58.9712313 12 27 37.5245541 284.958221 12 27 37.5245541 284.958221 12 27 37.5245541 284.958221 SAMPLE 2:下例計算1998年4月每天的累積交易數量 SELECT UNIQUE t.day_number_in_month, REGR_COUNT(s.amount_sold, s.quantity_sold) OVER (PARTITION BY t.fiscal_month_number ORDER BY t.day_number_in_month) "Regr_Count" FROM sales s, times t WHERE s.time_id = t.time_id AND t.fiscal_year = 1998 AND t.fiscal_month_number = 4; DAY_NUMBER_IN_MONTH Regr_Count ------------------- ---------- 1 825 2 1650 3 2475 4 3300 26 21450 30 22200 SAMPLE 3:下例計算1998年每月銷售量中已開發票數量和總數量的累積回歸線決定繫數 SELECT t.fiscal_month_number, REGR_R2(SUM(s.amount_sold), SUM(s.quantity_sold)) OVER (ORDER BY t.fiscal_month_number) "Regr_R2" FROM sales s, times t WHERE s.time_id = t.time_id AND t.fiscal_year = 1998 GROUP BY t.fiscal_month_number ORDER BY t.fiscal_month_number; FISCAL_MONTH_NUMBER Regr_R2 ------------------- ---------- 1 2 1 3 .927372984 4 .807019972 5 .932745567 6 .94682861 7 .965342011 8 .955768075 9 .959542618 10 .938618575 11 .880931415 12 .882769189 SAMPLE 4:下例計算1998年12月最後兩周產品260的銷售量中已開發票數量和總數量的累積平均值 SELECT t.day_number_in_month, REGR_AVGY(s.amount_sold, s.quantity_sold) OVER (ORDER BY t.fiscal_month_desc, t.day_number_in_month) "Regr_AvgY", REGR_AVGX(s.amount_sold, s.quantity_sold) OVER (ORDER BY t.fiscal_month_desc, t.day_number_in_month) "Regr_AvgX" FROM sales s, times t WHERE s.time_id = t.time_id AND s.prod_id = 260 AND t.fiscal_month_desc = '1998-12' AND t.fiscal_week_number IN (51, 52) ORDER BY t.day_number_in_month; DAY_NUMBER_IN_MONTH Regr_AvgY Regr_AvgX ------------------- ---------- ---------- 14 882 24.5 14 882 24.5 15 801 22.25 15 801 22.25 16 777.6 21.6 18 642.857143 17.8571429 18 642.857143 17.8571429 20 589.5 16.375 21 544 15.1111111 22 592.363636 16.4545455 22 592.363636 16.4545455 24 553.846154 15.3846154 24 553.846154 15.3846154 26 522 14.5 27 578.4 16.0666667 SAMPLE 5:下例計算產品260和270在1998年2月周末銷售量中已開發票數量和總數量的累積REGR_SXY, REGR_SXX, and REGR_SYY統計值 SELECT t.day_number_in_month, REGR_SXY(s.amount_sold, s.quantity_sold) OVER (ORDER BY t.fiscal_year, t.fiscal_month_desc) "Regr_sxy", REGR_SYY(s.amount_sold, s.quantity_sold) OVER (ORDER BY t.fiscal_year, t.fiscal_month_desc) "Regr_syy", REGR_SXX(s.amount_sold, s.quantity_sold) OVER (ORDER BY t.fiscal_year, t.fiscal_month_desc) "Regr_sxx" FROM sales s, times t WHERE s.time_id = t.time_id AND prod_id IN (270, 260) AND t.fiscal_month_desc = '1998-02' AND t.day_number_in_week IN (6,7) ORDER BY t.day_number_in_month; DAY_NUMBER_IN_MONTH Regr_sxy Regr_syy Regr_sxx ------------------- ---------- ---------- ---------- 1 18870.4 2116198.4 258.4 1 18870.4 2116198.4 258.4 1 18870.4 2116198.4 258.4 1 18870.4 2116198.4 258.4 7 18870.4 2116198.4 258.4 8 18870.4 2116198.4 258.4 14 18870.4 2116198.4 258.4 15 18870.4 2116198.4 258.4 21 18870.4 2116198.4 258.4 22 18870.4 2116198.4 258.4 92。ROW_NUMBER 功能描述:返回有序組中一行的偏移量,從而可用於按特定標準排序的行號。 SAMPLE:下例返回每個員工再在每個部門中按員工號排序後的順序號 SELECT department_id, last_name, employee_id, ROW_NUMBER() OVER (PARTITION BY department_id ORDER BY employee_id) AS emp_id FROM employees WHERE department_id < 50; DEPARTMENT_ID LAST_NAME EMPLOYEE_ID EMP_ID ------------- ------------------------- ----------- ---------- 10 Whalen 200 1 20 Hartstein 201 1 20 Fay 202 2 30 Raphaely 114 1 30 Khoo 115 2 30 Baida 116 3 30 Tobias 117 4 30 Himuro 118 5 30 Colmenares 119 6 40 Mavris 203 1 93。STDDEV 功能描述:計算當前行關於組的標準偏離。(Standard Deviation) SAMPLE:下例返回部門30按雇佣日期排序的薪水值的累積標準偏離 SELECT last_name, hire_date,salary, STDDEV(salary) OVER (ORDER BY hire_date) "StdDev" FROM employees WHERE department_id = 30; LAST_NAME HIRE_DATE SALARY StdDev ------------------------- ---------- ---------- ---------- Raphaely 07-12月-94 11000 0 Khoo 18-5月 -95 3100 5586.14357 Tobias 24-7月 -97 2800 4650.0896 Baida 24-12月-97 2900 4035.26125 Himuro 15-11月-98 2600 3649.2465 Colmenares 10-8月 -99 2500 3362.58829 94。STDDEV_POP 功能描述:該函數計算總體標準偏離,並返回總體變數的平方根,其返回值與VAR_POP函數的平方根相同。(Standard Deviation-Population) SAMPLE:下例返回部門20、30、60的薪水值的總體標準偏差 SELECT department_id, last_name, salary, STDDEV_POP(salary) OVER (PARTITION BY department_id) AS pop_std FROM employees WHERE department_id in (20,30,60); DEPARTMENT_ID LAST_NAME SALARY POP_STD ------------- ------------------------- ---------- ---------- 20 Hartstein 13000 3500 20 Fay 6000 3500 30 Raphaely 11000 3069.6091 30 Khoo 3100 3069.6091 30 Baida 2900 3069.6091 30 Colmenares 2500 3069.6091 30 Himuro 2600 3069.6091 30 Tobias 2800 3069.6091 60 Hunold 9000 1722.32401 60 Ernst 6000 1722.32401 60 Austin 4800 1722.32401 60 Pataballa 4800 1722.32401 60 Lorentz 4200 1722.32401 95。STDDEV_SAMP 功能描述: 該函數計算累積樣本標準偏離,並返回總體變數的平方根,其返回值