发布时间：2025-06-24 20:20:53  作者：北方职教升学中心  阅读量：742


T_update02select * from T_update01; ID INFONAME SYS_GUID---------- ------------------------------ ------------------------------------ 1 1_updateName 189F5A1099BF6606E0639C0AA8C0F15E 2 2_updateName 189F5A1099C06606E0639C0AA8C0F15Eselect * from T_update02; ID INFONAME SYS_GUID---------- ------------------------------ ------------------------------------ 1 update_set_exists 189F5A1099C46606E0639C0AA8C0F15E 2 update_set_cursor 189F5A1099C56606E0639C0AA8C0F15E 3 3_Name 189F5A1099C66606E0639C0AA8C0F15E

2、使用游标

-- T_update02数据更新一下，方便使用游标更新的结果显示update T_update02 set INFONAME='cursor is select' where id>=2;commit;select * from T_update02;        ID INFONAME                       SYS_GUID---------- ------------------------------ ------------------------------------         1 update_set_exists              189F5A1099C46606E0639C0AA8C0F15E         2 cursor is select               189F5A1099C56606E0639C0AA8C0F15E         3 cursor is select               189F5A1099C66606E0639C0AA8C0F15E-- 使用用游标更新T_update01的INFONAME字段，使其和T_update02 where id>=2declare  cursor cur_my_source is select infoname,id from T_update02;  begin     for cur_my_target in cur_my_source loop       update T_update01 set infoname=cur_my_target.infoname where id=cur_my_target.id;     end loop;	 commit; end; /-- 检查查询结果select * from T_update01;        ID INFONAME                       SYS_GUID---------- ------------------------------ ------------------------------------         1 update_set_exists              189F5A1099C46606E0639C0AA8C0F15E         2 cursor is select               189F5A1099C56606E0639C0AA8C0F15E         3 cursor is select               189F5A1099C66606E0639C0AA8C0F15E

4、update set 单列字段

-- update set 单列字段，更新满足关联条件的所有数据update T_update01 T1set infoname=(select T2.infoname from T_update02 T2 where T2.ID=T1.ID)where exists (select 1 from T_update02 T2 where T2.ID=T1.ID );-- update set 单列字段 ，更新满足特定条件ID=1的数据update T_update01 T1set infoname=(select T2.infoname from T_update02 T2 where T2.ID=T1.ID)where T1.ID=1;-- 本次执行更新满足特定条件T_update01表的ID=1SCOTT@prod02> select * from T_update01;        ID INFONAME                       SYS_GUID---------- ------------------------------ ------------------------------------         1 update_set_exists              189F5A1099BF6606E0639C0AA8C0F15E         2 2_updateName                   189F5A1099C06606E0639C0AA8C0F15E

2.2、测试表及数据准备

create table T_update01(ID int ,infoname varchar2(32),sys_guid varchar2(36));create table T_update02(ID int ,infoname varchar2(32),sys_guid varchar2(36));insert into T_update01select 1,N'1_updateName',sys_guid() from dualunionselect 2,N'2_updateName',sys_guid() from dual;commit;insert into T_update02select 1,N'update_set_exists',sys_guid() from dual;insert into T_update02select 2,N'update_set_cursor',sys_guid() from dual;insert into T_update02select 3,N'3_Name',sys_guid() from dual;commit;-- 查询表T_update01、update set 多列字段
-- T_update01表多插入一行数据insert into T_update01select 3,N'insert03',sys_guid() from dual;commit;select * from T_update01;        ID INFONAME                       SYS_GUID---------- ------------------------------ ------------------------------------         1 update_set_exists              189F5A1099BF6606E0639C0AA8C0F15E         2 2_updateName                   189F5A1099C06606E0639C0AA8C0F15E         3 insert03                       189F5A1099C76606E0639C0AA8C0F15Eupdate T_update01 T1 set (sys_guid,infoname) = (select T2.sys_guid,T2.infoname from T_update02 T2 where T2.ID=T1.ID)where exists (select 1 from T_update02 T2 where T2.ID=T1.ID );commit;-- 更新后检查，sys_guid,infoname两列的值和T_update02一样了select * from T_update01;        ID INFONAME                       SYS_GUID---------- ------------------------------ ------------------------------------         1 update_set_exists              189F5A1099C46606E0639C0AA8C0F15E         2 update_set_cursor              189F5A1099C56606E0639C0AA8C0F15E         3 3_Name                         189F5A1099C66606E0639C0AA8C0F15Eselect * from T_update02;        ID INFONAME                       SYS_GUID---------- ------------------------------ ------------------------------------         1 update_set_exists              189F5A1099C46606E0639C0AA8C0F15E         2 update_set_cursor              189F5A1099C56606E0639C0AA8C0F15E         3 3_Name                         189F5A1099C66606E0639C0AA8C0F15E
3、关联更新update
TESTUSER@FREEPDB1> create table t_emp as select EMPLOYEE_ID,DEPARTMENT_ID,SALARY from employees;Table created.TESTUSER@FREEPDB1> desc t_emp; Name                                      Null?    Type ----------------------------------------- -------- ---------------------------- EMPLOYEE_ID                                        NUMBER(6) DEPARTMENT_ID                                      NUMBER(4) SALARY                                             NUMBER(8,2)TESTUSER@FREEPDB1> select * from t_emp where DEPARTMENT_ID=110;EMPLOYEE_ID DEPARTMENT_ID     SALARY----------- ------------- ----------        205           110      12008        206           110       8300TESTUSER@FREEPDB1> update t_emp set DEPARTMENT_ID=null,SALARY=null where DEPARTMENT_ID=110;2 rows updated.TESTUSER@FREEPDB1> commit;Commit complete.TESTUSER@FREEPDB1> select * from t_emp where DEPARTMENT_ID is null;EMPLOYEE_ID DEPARTMENT_ID     SALARY----------- ------------- ----------        178                     7000        205        206-- oracle 23c SQL增强 表关联更新        TESTUSER@FREEPDB1> update t_emp t1 set t1.DEPARTMENT_ID=t2.DEPARTMENT_ID,t1.SALARY=t2.SALARY from employees t2 where t2.EMPLOYEE_ID=t1.EMPLOYEE_ID and t1.DEPARTMENT_ID is null;3 row updated.TESTUSER@FREEPDB1> commit;Commit complete.TESTUSER@FREEPDB1> select t1.* from t_emp t1 where t1.DEPARTMENT_ID=110;EMPLOYEE_ID DEPARTMENT_ID     SALARY----------- ------------- ----------        205           110      12008        206           110       8300
5.2、
1、update set column ... where exists
2.1、Oracle 23c/AI 新特性
不论是已发版本Oracle23c free还是最终发布的长期支持的Oracle23Ai，表关联更新update和删除delete语句易用且更加优雅，类似SQLServer的关联更新
以下操作基于的环境
SQL*Plus: Release 23.0.0.0.0 - Developer-Release on Fri May 17 11:17:54 2024
Version 23.2.0.0.0

5.1、merge into子句
create table T_merg01(ID int ,infoname varchar2(32),sys_guid varchar2(36));create table T_merg02(ID int ,infoname varchar2(32),sys_guid varchar2(36));insert into T_merg01select 1,N'1_Name',sys_guid() from dualunionselect 2,N'2_Name',sys_guid() from dual;commit;select * from T_merg01;        ID INFONAME                       SYS_GUID---------- ------------------------------ ------------------------------------         1 1_Name                         189F5A1099BB6606E0639C0AA8C0F15E         2 2_Name                         189F5A1099BC6606E0639C0AA8C0F15Einsert into T_merg02select 1,N'merge_into_Name1',sys_guid() from dual;insert into T_merg02 select 3,N'3_Name',sys_guid() from dual;select * from T_merg02;        ID INFONAME                       SYS_GUID---------- ------------------------------ ------------------------------------         1 merge_into_Name1               189F5A1099BD6606E0639C0AA8C0F15E         3 3_Name                         189F5A1099BE6606E0639C0AA8C0F15Emerge into T_merg01 T1using T_merg02 T2 on (T1.id=T2.id)when matched then update set infoname=T2.infonamewhen not matched then insert (ID,infoname,sys_guid) values(T2.ID ,T2.infoname,T2.sys_guid);commit;select * from T_merg01;        ID INFONAME                       SYS_GUID---------- ------------------------------ ------------------------------------         1 merge_into_Name1               189F5A1099BB6606E0639C0AA8C0F15E         2 2_Name                         189F5A1099BC6606E0639C0AA8C0F15E         3 3_Name                         189F5A1099BE6606E0639C0AA8C0F15E-- 可以发现T_merg01表的ID=1的INFONAME=merge_into_Name1和T_merg02表ID=1的值一样了-- 可以发现T_merg01表多了一行数据是T_merg02表ID=3的这一行数据
5、关联删除delete
TESTUSER@FREEPDB1> delete t_emp t1 from employees t2 where t2.EMPLOYEE_ID=t1.EMPLOYEE_ID and t2.DEPARTMENT_ID=110;45 rows deleted.TESTUSER@FREEPDB1> commit;Commit complete.TESTUSER@FREEPDB1> select t1.* from t_emp t1 where t1.DEPARTMENT_ID=110;no rows selected
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