如何为MySQL中包含记录的现有表创建唯一索引

Here i like to explain my problem,

在这里,我想解释一下我的问题,

I Need to Create Unique Index in my Existing table, and the table contains many records.

我需要在现有表中创建唯一索引,该表包含许多记录。

I tried to execute this code

我试着执行这段代码

CREATE UNIQUE INDEX empid_name ON employee (importcompany_id, employee_id, name, relationship);

but am getting error as

但我得到的错误是

#1062 - Duplicata du champ '0-Emp ID-Member Name-Relationship' pour la clef 'empid_name'

Help me to sort out this problem, i need to make fields unique

帮我解决这个问题,我需要让字段独一无二

Updated :

The reason for setting these fields unique is

设置这些字段唯一的原因是

Actually i have a table like this

其实我有一张这样的桌子

id  company_ID  Employee_ID Name        Relationship    Dob     Age Gender       
1   EMPL        00001       Choodamani  Spouse      11-Aug-66   49  Female            
2   EMPL        00001       Komala      Mother      30-Oct-39   76  Female            
3   EMPL        00001       Varshini    Daughter    29-Apr-04   11  Female            
4   EMPL        00001       Vasudevan   Employee    15-Jul-62   53  Male    
5   EMPL        00002       Siddharth   Son         1-Jun-00    15  Male              
6   EMPL        00002       Poongavanam Mother      21-Oct-39   76  Female            
7   EMPL        00002       Aruna       Spouse      16-Sep-68   47  Female            
8   EMPL        00002       Abirami     Daughter    7-May-97    18  Female            
9   EMPL        00002       Murali      Employee    7-Oct-67    48  Male

if have insert a data like this,

如果要插入这样的数据,

    id  company_ID  Employee_ID Name        Relationship    Dob     Age Gender       
    1   EMPL        00001       Choodamani  Spouse      11-Aug-70   45  Female            
    2   EMPL        00001       Nirmal      Son      30-Oct-39   76  Female

this insert or update is done through import using excel sheet

此插入或更新是通过使用Excel工作表导入完成的

3 个解决方案

#1

If you want to have unique index empid_name ON employee table with columns (importcompany_id, employee_id, name, relationship). Then you must delete existing duplicate data.

如果要在列员工表上使用唯一索引empid_name ON(importcompany_id,employee_id,name,relationship)。然后,您必须删除现有的重复数据。

Easy way to do this is to add a UNIQUE index on the 4 columns. When you write the ALTER statement, include the IGNORE keyword. Like so:

简单的方法是在4列上添加UNIQUE索引。编写ALTER语句时,请包含IGNORE关键字。像这样:

ALTER IGNORE TABLE `employee` ADD UNIQUE INDEX(importcompany_id, employee_id, name, relationship);

This will drop all the duplicate rows. As an added benefit, future INSERTs that are duplicates will error out. As always, you may want to take a backup before running something like this.

这将删除所有重复的行。作为一个额外的好处,未来的重复INSERT将会出错。与往常一样,您可能希望在运行此类内容之前进行备份。

Or Add primary key in your table then you can easily remove duplicates from your table. And then add unique index.

或者在表格中添加主键,然后您可以轻松地从表格中删除重复项。然后添加唯一索引。

3 个解决方案

#1

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