Question

我有一个像这样的mysql表：

   id   employee_number  name
    1        1             A
    2        2             B
    3        3             C
    4        3             C
    5        4             D
    6        5             E
    7        5             E            
    8        6             F
    9        7             G
    8        8             H
    9        9             I
   10      ....    
   11      ....
   12      ....
        many duplicated 
        employee_number

我想删除1行employee_number 3和5（id 3或4和6或7无关紧要）。我可以使用以下sql查看重复的行，但不知道下一步该怎么做。如果有人可以帮我解决这个问题，我会说。非常感谢！

SELECT COUNT( id ) , employee_number
FROM  `employees` 
GROUP BY employee_number

更新

CREATE TABLE new_table as SELECT * FROM old_table WHERE 1 GROUP BY employee_number;

好。我找到了这个陈述并且它有效。多谢你们。

Answer 1

DELETE FROM `employees`
WHERE ID 
NOT IN 
(SELECT MAX(B.ID) FROM 
                  (SELECT employee_number
                   FROM `employees`
                   GROUP BY employee_number
                   HAVING COUNT(*)>1) A,
                   `employees` B
 WHERE A.employee_number=B.employee_number
 GROUP BY B.employee_number
);

Answer 2

你可以像这样使用SQL（在oracle中）：查询重复的行 SELECT * FROM employees t1，其中t1.rowid＆gt; （SELECT min（t2.rowid）FROM employees t2，其中t2.name = t1.name）;

删除fromv employees t1，其中t1.rowid＆gt;（从员工t2中选择min（t2.rowid），其中t2.no = t1.no）;

Answer 3

您可以自行加入表格。

假设不删除相同的记录。即，（不是Employee.id = vtable.id）

如果不是相同的记录，如果employee_number匹配，则删除。

delete from Employee
USING Employee, Employeeas vtable
WHERE (NOT Employee.id=vtable.id)
AND (Employee.employee_number=vtable.employee_number)

删除mysql中的重复行

3 个答案: