Multitable INSERT 的用法

最新推荐文章于 2023-11-30 18:50:39 发布

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最新推荐文章于 2023-11-30 18:50:39 发布

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分类专栏： oracle 文章标签： Oracle Multitable INSERT

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本文详细介绍了 SQL 中 Insert 语句的各种用法，包括基础插入、无条件与条件性多表插入、条件 FIRST 插入及 Pivoting 插入等，并通过具体实例展示了如何灵活运用这些插入方式来提高数据处理效率。

一、Insert基础用法

语法：

Insert Into 表名 (字段1,字段2,字段3...）

Values (值1,值2,值3...）

例子：

INSERT INTO departments(department_id, department_name,
manager_id, location_id)
VALUES (70, 'Public Relations', 100, 1700);

语法：

Insert Into 表名 (字段1,字段2,字段3...）

select 语句

不做任何解释，实在是没啥好说的〇_〇，注意别跟create table ...as select一样，insert中的select前面可没as ^_^

二、Unconditional INSERT ALL 用法

直接拿例子了：

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;

解释：将select查询出来的结果，每返回一行就分别插入表sal_history 和mgr_history 中，优点就是只做一次查询即可分别查询2个表，假如使用基础用法，将进行2次查询。

三、Conditional INSERT ALL

还是直接拿例子：

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;

解释：将select查询出来的结果，每返回一行就判断，SAL > 10000 就插入表sal_history ，MGR > 200就插入mgr_history ，优点和前面提到一样。

四、Conditional FIRST INSERT

仍然是例子：

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;

解释：将select查询出来的结果，每返回一行就判断，SAL > 25000就插入表special_sal ，否则HIREDATE like ('%00%') ，符合就插入hiredate_history_00，前面2个条件还是不成力，就判断HIREDATE like ('%99%') ，符合就插入表hiredate_history_99 ，前面3个条件都不符合，只好插入表hiredate_history 了。

打完这我都头晕了，假如学过程序设计，看下面的清晰明了：

if SAL > 25000 then

INTO special_sal VALUES(DEPTID, SAL)
else

(

if HIREDATE like ('%00%') THEN

INTO hiredate_history_00 VALUES(DEPTID,HIREDATE)
else

(

if HIREDATE like ('%99%') THEN

INTO hiredate_history_99 VALUES(DEPTID, HIREDATE)
else

INTO hiredate_history VALUES(DEPTID, HIREDATE)
)

)

假如还看不理解，看官方的这句话吧，“If the first WHEN clause evaluates to true, the subsequent WHEN clauses for this row should be skipped.”

五、Pivoting INSERT

最后还是例子：

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;

解释：老实说，看不出有啥用法，真的非要说，咱就把它当作行列转换吧，如果上面表在加多一列，比如INTO sales_info VALUES (employee_id,week_id,week_which,sales_MON) 改成 INTO sales_info VALUES (employee_id,week_id,'星期一',sales_MON)

多表INSERT语句
1)INSERT...SELECT语句能够作为单个的DML语句的一部分用于插入行到多表中
2)多表INSERT语句能够被用在数据仓库系统中从一个或多个操作源转移数据到一组目的表中
3)Oracle9i引入下面的多表插入语句的类型：
-无条件INSERT
-条件ALL INSERT
-条件FIRST INSERT
-枢轴式(Pivoting)INSERT

无条件INSERT语句
语法：
INSERT ALL
[insert_into_value][values_clause]
(subquery)

例如：
-从emp表中选择empno大于7698雇员的empno，hiredate，sal和mgr值
-用多表INSERT插入这些值到sal_history(empno,hiredate,sal)和mgr_history(empno,mgr,sal)表中

INSERT ALL
INTO sal_history VALUES(empno,hiredate,sal)
INTO mgr_history VALUES(empno,mgr,sal)
SELECT empno,hiredate,sal,mgr
FROM emp
WHERE empno>7698;

有条件INSERT语句
语法
INSERT ALL
[WHEN condition THEN]
[insert_into_clause][values_clause]
(subquery)

例子
-从emp表中选择empno大于7698雇员的empno，hiredate，sal和mgr值
-如果sal大于$2500，用一个条件多表INSERT语句插入这些值到sal_history表中
-如果mgr大于7782，用一个多表INSERT语句插入这些值到mgr_history表中

INSERT ALL
WHEN sal>2500 THEN
INTO sal_history VALUES(empno,hiredate,sal)
WHEN mgr>7782 THEN
INTO mgr_history VALUES(empno,mgr,sal)
SELECT empno,hiredate,sal,mgr
FROM   emp
WHERE empno>7698;

条件FIRST INSERT
语法
INSERT FIRST
[WHEN condition THEN]
[insert_into_clause][values_clause]
[ELSE]
[insert_into_clause][values_clause]
(subquery)

例子
-从emp表中选择empno大于7698雇员的empno，hiredate，sal和mgr值
-如果sal大于$2500,则用一个条件FIRST多表INSERT语句插入这些值到sal_history表中
-如果第一个WHEN子句的值为true，则该行后面的WHEN子句被跳过
-如果mgr大于7782，用一个条件FIRST多表INSERT语句插入这些值到mgr_history表中

INSERT FIRST
WHEN sal>2500 THEN
INTO sal_history VALUES(empno,hiredate,sal)
WHEN mgr>7782 THEN
INTO mgr_history VALUES(empno,mgr,sal)
SELECT empno,hiredate,sal,mgr
FROM emp
WHERE empno>7698;

枢轴式(Pivoting) INSERT

支持从非关系数据库表中接受一组销售记录
sales_source_data的格式如下：
empno,week_id,sales_MON,sales_TUE,sales_WED,sales_THUR,sales_FRI
你可能想要以一种典型的相关格式存储这些记录到sales_info(empno,week,sales)表中使用pivoting INSERT，从非关系数据库表转换销售记录集到关系格式

INSERT ALL
INTO sales_info VALUES(empno,week_id,sales_MON)
INTO sales_info VALUES(empno,week_id,sales_TUE)
INTO sales_info VALUES(empno,week_id,sales_WED)
INTO sales_info VALUES(empno,week_id,sales_THUR)
INTO sales_info VALUES(empno,week_id,sales_FRI)
SELECT empno,week_id,sales_MON,sales_TUE,sales_WED,sales_THUR,sales_FRI
FROM sales_source_data;

什么是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)
);
-- 现在要将上表的数据转换到下表中，
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,

行转列