MAX(DISTINCTSAL)---------------- 5000
62.MIN(DISTINCT|ALL)求最小值,ALL表示对所有的值求最小值,DISTINCT表示对不同的值求最小值,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)求协方差
SQL> select variance(sal) from scott.emp;
VARIANCE(SAL)------------- 1398313.9
65.GROUP BY主要用来对一组数进行统计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对分组统计再加限制条件SQL> select deptno,count(*),sum(sal) from scott.emp group by deptno having nt(*)>=5;
DEPTNO COUNT(*) SUM(SAL)--------- --------- --------- 20 5 10875 30 6 9400SQL> select deptno,count(*),sum(sal) from scott.emp having count(*)>=5 group by tno ;
DEPTNO COUNT(*) SUM(SAL)--------- --------- --------- 20 5 10875 30 6 9400
67.ORDER BY用于对查询到的结果进行排序输出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