第三章 大数据集合
从一个表中拷贝数据
insert into sales(id,name,salary,commission_pct)
select employee_id,last_name,salary
from employees
where job_id like '%REP%';
将子查询作为insert的目标
INSERT INTO
(SELECT employee_id, last_name,
email, hire_date, job_id, salary,
department_id
FROM empl3
WHERE department_id = 50)
VALUES (99999, 'Taylor', 'DTAYLOR',
TO_DATE('07-JUN-99', 'DD-MON-RR'),
'ST_CLERK', 5000, 50);
获取数据使用子查询作为数据源
SELECT a.last_name, a.salary,
a.department_id, b.salavg
FROM employees a, (SELECT department_id,
AVG(salary) salavg
FROM employees
GROUP BY department_id) b
WHERE a.department_id = b.department_id
AND a.salary > b.salavg;
update emp
set job_id=(select job_id from employees
where employee_id=205
)
,salary=( select salary from employees
where employee_id=205
)
where employee_id=114;
INSERT ALL插入多个表的数据
语法
INSERT ALL
INTO table_a VALUES(…,…,…)
INTO table_b VALUES(…,…,…)
INTO table_c VALUES(…,…,…)
SELECT …
FROM sourcetab
WHERE …;
例如一：
INSERT ALL
INTO sal_history VALUES(EMPID,HIREDATE,SAL)
INTO mgr_history VALUES(EMPID,MGR,SAL)
SELECT employee_id EMPID, hire_date HIREDATE,
salary SAL, manager_id MGR
FROM employees
WHERE employee_id > 200;
例如二：
INSERT ALL
WHEN SAL > 10000 THEN
INTO sal_history VALUES(EMPID,HIREDATE,SAL)
WHEN MGR > 200 THEN
INTO mgr_history VALUES(EMPID,MGR,SAL)
SELECT employee_id EMPID,hire_date HIREDATE,
salary SAL, manager_id MGR
FROM employees
WHERE employee_id > 200;
实例三：
INSERT FIRST
WHEN SAL > 25000 THEN
INTO special_sal VALUES(DEPTID, SAL)
WHEN HIREDATE like ('%00%') THEN
INTO hiredate_history_00 VALUES(DEPTID,HIREDATE)
WHEN HIREDATE like ('%99%') THEN
INTO hiredate_history_99 VALUES(DEPTID, HIREDATE)
ELSE
INTO hiredate_history VALUES(DEPTID, HIREDATE)
SELECT department_id DEPTID, SUM(salary) SAL,
MAX(hire_date) HIREDATE FROM employees
GROUP BY department_id;
实例四：
INSERT ALL
INTO sales_info VALUES(employee_id,week_id,sales_MON)
INTO sales_info VALUES(employee_id,week_id,sales_TUE)
INTO sales_info VALUES(employee_id,week_id,sales_WED)
INTO sales_info VALUES(employee_id,week_id,sales_THUR)
INTO sales_info VALUES(employee_id,week_id,sales_FRI)
SELECT employe_id,week_id,sales_mon,sales_tue,sales_wed,sales_thur,sale_pri
FROM sales_source_data;
MERGE语句的使用：
语法：
MERGE INTO table_name table_alias
USING (table|view|sub_query) alias
ON (join condition)
WHEN MATCHED THEN
UPDATE SET
col1 = col_val1,
col2 = col2_val
WHEN NOT MATCHED THEN
INSERT (column_list)
VALUES (column_values);
例如：插入或者更新empl3表信息
MERGE INTO empl3 c
USING employees e
ON (c.employee_id = e.employee_id)
WHEN MATCHED THEN
UPDATE SET
c.first_name = e.first_name,
c.last_name = e.last_name,
...
c.department_id = e.department_id
WHEN NOT MATCHED THEN
INSERT VALUES(e.employee_id, e.first_name, e.last_name,
e.email, e.phone_number, e.hire_date, e.job_id,
e.salary, e.commission_pct, e.manager_id,
e.department_id);
第四章分组相关的函数
语法：
SELECT [column,] group_function(column)...
FROM table
[WHERE condition]
[GROUP BY group_by_expression]
[HAVING having_expression]
[ORDER BY column];
SELECT department_id, job_id, SUM(salary),
COUNT(employee_id)
FROM employees
GROUP BY department_id, job_id ;
SELECT department_id, job_id, SUM(salary)
FROM employees
WHERE department_id < 60
GROUP BY ROLLUP(department_id, job_id);
SELECT department_id, job_id, SUM(salary)
FROM employees
WHERE department_id < 60
GROUP BY CUBE (department_id, job_id) ;
SELECT department_id DEPTID, job_id JOB,
SUM(salary),
GROUPING(department_id) GRP_DEPT,
GROUPING(job_id) GRP_JOB
FROM employees
WHERE department_id < 50
GROUP BY ROLLUP(department_id, job_id);
SELECT department_id, job_id,
manager_id,avg(salary)
FROM employees
GROUP BY GROUPING SETS((department_id,job_id), (job_id,manager_id));
SELECT department_id, job_id, manager_id,
SUM(salary)
FROM employees
GROUP BY ROLLUP( department_id,(job_id, manager_id));
SELECT department_id, job_id, manager_id,
SUM(salary)
FROM employees
GROUP BY department_id,
ROLLUP(job_id),
CUBE(manager_id);
