SQL 输出中的重复行值过多

Question

我创建了一个查询来删除表中的重复行。我试图这样做，但输出是“太多值”

DELETE FROM Employeetest 
WHERE employeeid IN (SELECT 
                         employeetest.*, 
                         ROW_NUMBER() OVER (PARTITION BY employeeid ORDER BY employeeid) AS rownumber 
                     FROM
                         employeetest 
                     HAVING
                         (rownumber > 1)); 

我也是

SELECT
    employeetest.*, 
    ROW_NUMBER() OVER (PARTITION BY employeeid ORDER BY employeeid) AS rownumber 
FROM
    employeetest

然后

DELETE * FROM employeetest;

没有用

Answer 1

你标记为 plsql 我知道你的 DB 是 Oracle。所以你可以使用rowid pseudocolumn，如下所示：

delete Employeetest t1
where rowid <
(
select max(rowid)
  from Employeetest t2 
 where t2.employeeid = t1.employeeid 
);

如果目标是删除 employeeid 值的所有重复项。

附注无法以Delete * from employeetest where ... 这样的方式删除，但可以使用Delete from employeetest where ... 或Delete employeetest where ...。

Answer 2

我总是使用这样的东西：

delete employeetest
where  rowid in
       ( select lag(rowid) over (partition by employeeid order by null) 
         from employeetest )

Answer 3

这个逻辑通常也写成：

delete Employeetest 
where rowid in (select max(rowid)
                from Employeetest e2
                group by e2.employeeid
               );