oracle¼¼Êõ£ºORACLE ³£Óú¯Êý¡ª¡ª¾ÛºÏº¯Êý£¬AVG¡¢MAX¡¢MIN¡¢STDDEV¡¢VARIANCE¡¢SUM¡¢COUNT¡¢MEDIAN

--1: AVG(DISTINCT|ALL)

ALL±íʾ¶ÔËùÓеÄÖµÇóƽ¾ùÖµ,DISTINCTÖ»¶Ô²»Í¬µÄÖµÇóƽ¾ùÖµ

SELECT AVG(SAL) FROM SCOTT.EMP;

SELECT AVG(DISTINCT SAL) FROM SCOTT.EMP;

--2: MAX(DISTINCT|ALL)

Çó×î´óÖµ,ALL±íʾ¶ÔËùÓеÄÖµÇó×î´óÖµ,DISTINCT±íʾ¶Ô²»Í¬µÄÖµÇó×î´óÖµ,ÏàͬµÄֻȡһ´Î

(¼Ó²»¼Ó²éѯ½á¹ûÒ»Ö£¬²»ÖªDISTINCTÓÐʲôÓÃ;£¬²»Í¬ÓÚAVGµÈ¾ÛºÏº¯Êý)

SELECT MAX(DISTINCT SAL) FROM SCOTT.EMP;

SELECT MAX(SAL) FROM SCOTT.EMP

--3: MIN(DISTINCT|ALL)

Çó×îСֵ,ALL±íʾ¶ÔËùÓеÄÖµÇó×îСֵ,DISTINCT±íʾ¶Ô²»Í¬µÄÖµÇó×îСֵ,ÏàͬµÄֻȡһ´Î

SELECT MIN(SAL) FROM SCOTT.EMP;

SELECT MIN(DISTINCT SAL) FROM SCOTT.EMP;

--4: STDDEV(distinct|all)

Çó±ê×¼²î,ALL±íʾ¶ÔËùÓеÄÖµÇó±ê×¼²î,DISTINCT±íʾֻ¶Ô²»Í¬µÄÖµÇó±ê×¼²î

SELECT STDDEV(SAL) FROM SCOTT.EMP;

SELECT STDDEV(DISTINCT SAL) FROM SCOTT.EMP;

--5: VARIANCE(DISTINCT|ALL)

ÇóЭ·½²î ALL±íʾ¶ÔËùÓеÄÖµÇóЭ·½²î,DISTINCT±íʾֻ¶Ô²»Í¬µÄÖµÇóЭ·½²î

SELECT VARIANCE(SAL) FROM SCOTT.EMP;

SELECT VARIANCE(DISTINCT SAL) FROM SCOTT.EMP;

--6: SUM(DISTINCT|ALL)

ÇóºÍ ALL±íʾ¶ÔËùÓÐÖµÇóºÍ£¬DISTINCT±íʾֻ¶Ô²»Í¬ÖµÇóºÍ(Ïàֵֻͬȡһ´Î)

SELECT SUM(SAL) FROM SCOTT.EMP;

SELECT SUM(DISTINCT SAL) FROM SCOTT.EMP;

--7£ºCOUNT(DISTINCT|ALL)

Çó¼Ç¼¡¢Êý¾Ý¸öÊý¡£ ALL¶ÔËùÓмǼ£¬Êý×é×öͳ¼Æ£¬ DISTINCTÖ»¶Ô²»Í¬ÖµÍ³¼Æ(Ïàֵֻͬȡһ´Î)

SELECT COUNT(SAL) FROM SCOTT.EMP;

SELECT COUNT(DISTINCT SAL) FROM SCOTT.EMP;

----8£º MEDIAN

ÇóÖÐλÊý

SELECT MEDIAN(SAL) FROM SCOTT.EMP;

SELECT MEDIAN(DISTINCT SAL) FROM SCOTT.EMP; --´íÎó£ºDISTINCT Ñ¡ÏîÔڴ˺¯ÊýÖнûÓá£