Question

我有两个相似的表（Table_A和Table_B），它们共享相同的唯一标识符（Column Employee_Number列）。他们也有类似的数据。

Create table Table_A
(
    Employee_Number varchar2(100),
    name            varchar2(100),
    address         varchar2(100),
    tel_no          varchar2(100),
    social_sec_no   varchar2(100)
);

INSERT INTO Table_A  (Employee_Number, name, address, tel_no, social_sec_no) values ('1', 'emp 1', 'home1', '1111', '11111');
INSERT INTO Table_A  (Employee_Number, name, address, tel_no, social_sec_no) values ('2', 'emp 2', 'home2', '2222', '22222');
INSERT INTO Table_A  (Employee_Number, name, address, tel_no, social_sec_no) values ('3', 'emp 3', 'home3', '3333', '33333');
INSERT INTO Table_A  (Employee_Number, name, address, tel_no, social_sec_no) values ('4', 'emp 4', 'home4', '4444', '44444');
INSERT INTO Table_A  (Employee_Number, name, address, tel_no, social_sec_no) values ('5', 'emp 5', 'home5', '5555', '55555');

commit;

create table Table_b
as
select  *
from    Table_A;

然而，表B中的一条记录发生了变化：

update  Table_b
set     social_sec_no = '99999'
where   Employee_Number = '1';

update  Table_b
set     social_sec_no = 'xxxx'
where   Employee_Number = '3';

update  Table_b
set     address = 'office'
where   Employee_Number = '1';

commit;

我这样做是为了找出哪些列被更改了：

SELECT  *
FROM    (select AX.Employee_Number
              , CASE WHEN AX.name          <> bx.NAME          THEN 'CHANGED' else 'NO_CHANGE' END  name
              , CASE WHEN AX.address       <> bx.address       THEN 'CHANGED' else 'NO_CHANGE' END  address
              , CASE WHEN AX.tel_no        <> bx.tel_no        THEN 'CHANGED' else 'NO_CHANGE' END  tel_no
              , CASE WHEN AX.social_sec_no <> bx.social_sec_no THEN 'CHANGED' else 'NO_CHANGE' END  social_sec_no
        from    Table_A ax
              , Table_B bx
        where   ax.Employee_Number = bx.Employee_Number
        and    (ax.name          <> bx.name
        or      ax.address       <> bx.address
        or      ax.tel_no        <> bx.tel_no
        or      ax.social_sec_no <> bx.social_sec_no))
WHERE   1=1
AND    (name          = 'CHANGED'
OR      address       = 'CHANGED'
OR      tel_no        = 'CHANGED'
OR      social_sec_no = 'CHANGED');

查询结果

Employee_Number NAME        ADDRESS     TEL_NO      SOCIAL_SEC_NO     
--------------- ---------   ---------   ---------   --------------
1               NO_CHANGE   CHANGED     NO_CHANGE   CHANGED
3               NO_CHANGE   NO_CHANGE   NO_CHANGE   CHANGED

我想知道是否有更好更有效的方法来找出哪个记录和列已更改不使用触发器或任何其他DDL和DML？

数据库详细信息：

Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
PL/SQL Release 11.2.0.4.0 - Production

谢谢！

Answer 1

主题的变化......许多年前在AskTom上解决了问题，感谢Marco Stefanelli提出核心理念。

select * 
from (
  select source, employee_number, name, address, tel_no, social_sec_no,
         count(*) over ( partition by employee_number, 
                       name, address, tel_no, social_sec_no) as cnt
  from (
         select 'table_a' as source, 
                employee_number, name, address, tel_no, social_sec_no
           from table_a
         union all
         select 'table_b' as source, 
                employee_number, name, address, tel_no, social_sec_no
           from table_b
       )
)
where cnt = 1
order by employee_number, source
;

SOURCE   EMPLOYEE_NUMBER NAME       ADDRESS      TEL_NO     SOCIAL_SEC_NO    CNT
-------  --------------- ---------- ------------ ---------- ------------- ------
table_a  1               emp 1      home1        1111       11111              1
table_b  1               emp 1      office       1111       99999              1
table_a  3               emp 3      home3        3333       33333              1
table_b  3               emp 3      home3        3333       xxxx               1

4 rows selected.

此查询还将识别一个表中不具有另一个表中的通信者（具有相同employee_number的行）的行。它的工作方式是，如果两个表中都存在完全相同的行，则count(*)为2。

如果要排除一个表中的行而不是另一个表中的行（完全没有匹配employee_number），请添加另一个＆＃34;列＆＃34;中间select，count(*) over (partition by employee_number) - 如果employee_number出现在一个表中而不出现在另一个表中，则该值为1，因此在外部查询的where子句中要求此号码为= 2。

一个更简单的版本（更难以＃34; hack＆＃34;排除那些在另一个表中没有匹配employee_number的行）：

select max(source) as source, 
       employee_number, name, address, tel_no, social_sec_no
from   (
         select 'table_a' as source, 
                employee_number, name, address, tel_no, social_sec_no
           from table_a
         union all
         select 'table_b' as source, 
                 employee_number, name, address, tel_no, social_sec_no
           from table_b
       )
group by employee_number, name, address, tel_no, social_sec_no
having count(*) = 1
order by employee_number, source
;

找出两个表之间更新的记录和列

1 个答案: