总结下Oracle 中的Insert用法
1.标准Insert --单表单行插入
语法:
INSERT INTO table [(column1,column2,...)] VALUE (value1,value2,...)
例子:
insert into dep (dep_id,dep_name) values(1,'技术部');
备注:使用标准语法只能插入一条数据,且只能在一张表中插入数据
2, 无条件 Insert all --多表多行插入
语法:
INSERT [ALL] [condition_insert_clause]
[insert_into_clause values_clause] (subquery)
示例:
INSERT ALL
INTO sal_history(emp_id,hire_date,salary) values (empid,hiredate,sal)
INTO mgr_history(emp_id,manager_id,salary) values (empid,hiredate,sal)
SELECT employee_id empid,hire_date hiredate,salary sal,manager_id mgr
FROM employees
WHERE employee_id>200;
3,有条件的Insert
语法:
INSERT [ALL | FIRST]
WHEN condition THEN insert_into_clause values_clause
[WHEN condition THEN] [insert_into_clause values_clause]
......
[ELSE] [insert_into_clause values_clause]
Subquery；
示例:
Insert All
when id>5 then into z_test1(id, name) values(id,name)
when id<>2 then into z_test2(id) values(id)
else into z_test3 values(name)
select id,name from z_test;
当使用ALL关键字时,oracle会从上至下判断每一个条件,当条件满足时就执行后面的into语句
在上面的例子中,如果ID=6 那么将会在z_test1中插入一条记录,同时也在z_test2中插入一条记录
备注:
当使用FIRST关键字时,oracle会从上至下判断每一个条件,当遇到第一个满足时就执行后面的into语句,
同时中断判断的条件判断,在上面的例子中,如果ID=6,仅仅会在z_test1中插入一条数据
4, 旋转Insert (pivoting insert)
create table sales_source_data (
employee_id number(6),
week_id number(2),
sales_mon number(8,2),
sales_tue number(8,2),
sales_wed number(8,2),
sales_thur number(8,2),
sales_fri number(8,2)
);
insert into sales_source_data values (176,6,2000,3000,4000,5000,6000);
create table sales_info (
employee_id number(6),
week number(2),
sales number(8,2)
);
看上面的表结构,现在将要sales_source_data表中的数据转换到sales_info表中,这种情况就需要使用旋转Insert
示例如下:
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 employee_id,week_id,sales_mon,sales_tue,
sales_wed,sales_thur,sales_fri
from sales_source_data;
从该例子可以看出,所谓旋转Insert是无条件 insert all 的一种特殊应用,但这种应用被oracle官方,赋予了一个pivoting insert的名称,即旋转insert