如何从mysql中的表中删除重复的行

Question

我需要从mysql中删除表中的重复记录.所以我有一个表名"employee"字段是empid,empname,empssn

为了获得重复记录我写了一个查询

     SELECT COUNT(empssn), empssn 
       FROM employee 
GROUP BY empssn 
    HAVING COUNT(empssn)>1

现在我想删除重复的记录.因为我有书面查询是.

DELETE FROM employee 
          WHERE (empid, empssn) NOT IN (SELECT MIN(empid), empssn 
                                                           FROM employee 
                                                    GROUP BY empssn);

你可以假设表中的记录是

EmpId  EmpName  EmpSSN
 -------------------------------
 1  Jack      555-55-5555
 2  Joe      555-56-5555
 3  Fred      555-57-5555
 4  Mike      555-58-5555
 5  Cathy      555-59-5555
 6  Lisa      555-70-5555
 7  Jack      555-55-5555
 8  Mike      555-58-5555
 9  Cathy      555-59-5555
10  Lisa      555-70-5555
11  Lisa      555-70-5555

但我有一个mysql错误是

您不能在FROM子句中为更新指定目标表'employee'

Answer 1

将它包装到派生表中的技巧是否适用于这种情况？(基于http://www.xaprb.com/blog/2006/06/23/how-to-select-from-an-update-target-in-mysql/)

DELETE FROM employee WHERE (empid, empssn) NOT IN 
(
SELECT  empid, empssn FROM
(
SELECT MIN(empid) AS empid, empssn FROM employee GROUP BY empssn
) X
);

编辑是的,似乎这样做.