sql函数复习

创建表
CREATE TABLE emp (
empno NUMBER(4) CONSTRAINT pk_emp PRIMARY KEY,
ename VARCHAR2(10),
job VARCHAR2(9),
mgr NUMBER(4),
hiredate DATE,
sal NUMBER(7,2),
comm NUMBER(7,2),
deptno NUMBER(2)
);

INSERT INTO emp VALUES (7369,‘SMITH’,‘CLERK’,7902,to_date(‘17-12-1980’,‘dd-mm-yyyy’),800,NULL,20);
INSERT INTO emp VALUES (7499,‘ALLEN’,‘SALESMAN’,7698,to_date(‘20-2-1981’,‘dd-mm-yyyy’),1600,300,30);
INSERT INTO emp VALUES (7521,‘WARD’,‘SALESMAN’,7698,to_date(‘22-2-1981’,‘dd-mm-yyyy’),1250,500,30);
INSERT INTO emp VALUES (7566,‘JONES’,‘MANAGER’,7839,to_date(‘2-4-1981’,‘dd-mm-yyyy’),2975,NULL,20);
INSERT INTO emp VALUES (7654,‘MARTIN’,‘SALESMAN’,7698,to_date(‘28-9-1981’,‘dd-mm-yyyy’),1250,1400,30);
INSERT INTO emp VALUES (7698,‘BLAKE’,‘MANAGER’,7839,to_date(‘1-5-1981’,‘dd-mm-yyyy’),2850,NULL,30);
INSERT INTO emp VALUES (7782,‘CLARK’,‘MANAGER’,7839,to_date(‘9-6-1981’,‘dd-mm-yyyy’),2450,NULL,10);
INSERT INTO emp VALUES (7788,‘SCOTT’,‘ANALYST’,7566,to_date(‘13-JUL-87’,‘dd-mm-rr’)-85,3000,NULL,20);
INSERT INTO emp VALUES (7839,‘KING’,‘PRESIDENT’,NULL,to_date(‘17-11-1981’,‘dd-mm-yyyy’),5000,NULL,10);
INSERT INTO emp VALUES (7844,‘TURNER’,‘SALESMAN’,7698,to_date(‘8-9-1981’,‘dd-mm-yyyy’),1500,0,30);
INSERT INTO emp VALUES (7876,‘ADAMS’,‘CLERK’,7788,to_date(‘13-JUL-87’, ‘dd-mm-rr’)-51,1100,NULL,20);
INSERT INTO emp VALUES (7900,‘JAMES’,‘CLERK’,7698,to_date(‘3-12-1981’,‘dd-mm-yyyy’),950,NULL,30);
INSERT INTO emp VALUES (7902,‘FORD’,‘ANALYST’,7566,to_date(‘3-12-1981’,‘dd-mm-yyyy’),3000,NULL,20);
INSERT INTO emp VALUES (7934,‘MILLER’,‘CLERK’,7782,to_date(‘23-1-1982’,‘dd-mm-yyyy’),1300,NULL,10);
COMMIT;
求和
SELECT SUM(sal) AS qiuhe
FROM emp;

SELECT deptno,
SUM(sal) AS fenzu_qiuhe
FROM emp
GROUP BY deptno
ORDER BY deptno;

不分区求和
SELECT empno,ename,deptno,sal,
SUM(sal) OVER () AS qiuhe
FROM emp;

对部门分区，在进行求和
SELECT empno,ename,deptno,sal,
SUM(sal) OVER (PARTITION BY deptno) AS fenqu_qiuhe
FROM emp;

对部门进行分区，在进行排序
SELECT empno,ename,deptno,sal,
SUM(sal) OVER (PARTITION BY deptno ORDER BY sal) AS paixu_fenqu
FROM emp;

不设置边界
SELECT empno,ename,deptno,sal,
SUM(sal) OVER (PARTITION BY deptno ORDER BY sal) AS paixu_fenqu,
SUM(sal) OVER (PARTITION BY deptno ORDER BY sal
RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS meibianjie
FROM emp;

SELECT empno,ename,deptno,sal,
SUM(sal) OVER (PARTITION BY deptno ORDER BY sal) AS paixu_fenqu,
SUM(sal) OVER (PARTITION BY deptno ORDER BY sal
ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS meibianjie
FROM emp

SELECT COUNT() AS count_total,
COUNT(sal) AS count_sal,
COUNT(comm) AS count_comm
FROM emp;

SELECT empno,ename,deptno,sal,
COUNT() OVER () AS amount
FROM emp;

SELECT empno,ename,deptno,sal,
COUNT(*) OVER (PARTITION BY deptno) AS amount_by_dept
FROM emp;

最大值，最小值
最高工资，最低工资
SELECT MIN(sal) AS min_sal,
MAX(sal) AS max_sal
FROM emp;

SELECT deptno,
MIN(sal) AS min_sal,
MAX(sal) AS max_sal
FROM emp
GROUP BY deptno
ORDER BY deptno;

SELECT empno,ename,deptno,sal,
MIN(sal) OVER () AS min_sal
FROM emp
ORDER BY deptno;

SELECT empno,ename,deptno,sal,
MIN(sal) OVER (PARTITION BY deptno) AS min_sal_by_dept
FROM emp
ORDER BY deptno;

SELECT empno,ename,deptno,sal,
MAX(sal) OVER () AS max_sal
FROM emp
ORDER BY deptno;

SELECT empno,ename,deptno,sal,
MAX(sal) OVER (PARTITION BY deptno) AS max_sal_by_dept
FROM emp
ORDER BY deptno;

SELECT AVG(sal) AS mean_sal,
MEDIAN(sal) AS media_sal
FROM emp;

SELECT deptno,
AVG(sal) AS mean_sal,
MEDIAN(sal) AS media_sal
FROM emp
GROUP BY deptno
ORDER BY deptno;

SELECT empno,ename,deptno,sal,
AVG(sal) OVER () AS mean_sal
FROM emp
ORDER BY deptno;

SELECT empno,ename,deptno,sal,
AVG(sal) OVER (PARTITION BY deptno) AS mean_sal_by_dept
FROM emp
ORDER BY deptno;

SELECT empno,ename,deptno,sal,
MEDIAN(sal) OVER () AS median_sal
FROM emp
ORDER BY deptno;

SELECT empno,ename,deptno,sal,
MEDIAN(sal) OVER (PARTITION BY deptno) AS median_sal_by_dept
FROM emp
ORDER BY deptno;