>SQL> select min(all sal) from gao.table3;
666
667MIN(ALLSAL)
668-----------
669 1111.11
670
671
67263.STDDEV(distinct|all)
673求标准差,ALL表示对所有的值求标准差,DISTINCT表示只对不同的值求标准差
674SQL> select stddev(sal) from scott.emp;
675
676STDDEV(SAL)
677-----------
678 1182.5032
679
680SQL> select stddev(distinct sal) from scott.emp;
681
682STDDEV(DISTINCTSAL)
683-------------------
684 1229.951
685
686
687
68864.VARIANCE(DISTINCT|ALL)
689求协方差
690
691SQL> select variance(sal) from scott.emp;
692
693VARIANCE(SAL)
694-------------
695 1398313.9
696
697
69865.GROUP BY
699主要用来对一组数进行统计
700SQL> select deptno,count(*),sum(sal) from scott.emp group by deptno;
701
702 DEPTNO COUNT(*) SUM(SAL)
703--------- --------- ---------
704 10 3 8750
705 20 5 10875
706 30 6 9400
707
708
709
71066.HAVING
711对分组统计再加限制条件
712SQL> select deptno,count(*),sum(sal) from scott.emp group by deptno having count(*)>=5;
713
714 DEPTNO COUNT(*) SUM(SAL)
715--------- --------- ---------
716 20 5 10875
717 30 6 9400
718SQL> select deptno,count(*),sum(sal) from scott.emp having count(*)>=5 group by deptno ;
719
720 DEPTNO COUNT(*) SUM(SAL)
721--------- --------- ---------
722 20 5 10875
723 30 6 9400
724
725
72667.ORDER BY
727用于对查询到的结果进行排序输出
728SQL> select deptno,ename,sal from scott.emp order by deptno,sal desc;
729
730 DEPTNO ENAME SAL
731--------- ---------- ---------
732 10 KING 5000
733 10 CLARK 2450
734 10 MILLER 1300
735 20 SCOTT 3000
736 20 FORD 3000
737 20 JONES 2975
738 20 ADAMS 1100
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