Oracle应用之insert all用法简介

雨点打透心脏的1/2处 2021-09-29 05:38 355阅读 0赞

insert all是oracle中用于批量写数据的

现在直接通过例子学习一下，比较简单直观，例子来自《收获，不止SQL优化》一书

环境准备

create table t as select object_name,rownum as object_id
    from dba_objects where rownum<=10;

创建两张测试表，不用写数据

create table t1 as select * from t where 1=2;
    create table t2 as select * from t where 1=2;

然后演示一下insert all的用法

**无条件写数据的情况**

insert all into t1
      (object_name, object_id) into t2
      (object_name, object_id)
      select * from t;
    commit;

**有条件写数据的情况**

truncate table t1;
    truncate table t2;
    insert all when object_id < 5 then into t1
      (object_name, object_id) when object_id >= 5 then into t2
      (object_name, object_id)
      select * from t;
    commit;

**insert first**  
insert first情况，介绍一下insert first的用法，insert first用法和insert all类似，区别的是insert first多了筛选的步骤，简单来说就是和insert all一样，符合条件的同样会写数据，不过已经存在数据了，insert first是不会写入的，而insert all是会出现重复数据的情况

truncate table t1;
    truncate table t2;
    insert first when object_id = 1 then into t1
      (object_name, object_id) when object_id <= 5 then into t2
      (object_name, object_id)
      select * from t;
    commit;

**pivoting insert**  
然后再演示一下pivoting insert的情况，pivoting insert可以说是insert all的一直特殊情况，不过oracle官方还是区分出来，pivoting insert可以翻译为旋转写入，名称的不重要，看一下例子就懂了

环境准备

drop table sales_source_data;
    create table sales_source_data(
    employee_id number(10),
    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(280,6,2000,3000,4000,5000,6000);
    commit;
    create table sales_info(
    employee_id number(10),
    week number(2),
    sales number(8,2)
    );

按照条件进行写数据

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;
    commit;