how to add unique key in mysql

If you need to add a unique key from mysql table. How can you add that using mysql query? There are two methods to add index in mysql.  One is MySql Query and another is GUI.  First Method to add using MySql Query: To add a unique key use : alter table your_table add UNIQUE(target_column_name); To add multiple column for a unique key use: ALTER TABLE ADD UNIQUE( column_name1, column_name2, column_name3); 

In this method you have to open GUI interface of MYSQL and then go to that database and then go to that particular table in which you want to add index.First you need to select one column or you can select multiple columns as required and then click on index option (here unique). That's all.

If you need to add a unique key from mysql table. How can you add that using mysql query?

There are two methods to add index in mysql.  One is MySql Query and another is GUI.

First Method to add using MySql Query:

To add a unique key use :

alter table your_table add UNIQUE(target_column_name);

To add multiple column for a unique key use:

ALTER TABLE ADD UNIQUE( column_name1, column_name2, column_name3);

To know the name of the index you want to delete or update

SHOW INDEX FROM

To delete an index

ALTER TABLE DROP INDEX ;

Second Method to add using MySql GUI (phpMyAdmin):

In this method you have to open GUI interface of MYSQL and then go to that database and then go to that particular table in which you want to add index.

After that click on the structure option, Then you can see table structure and below you can see table columns. First you need to select one column or you can select multiple columns as required and then click on index option (here unique). That's all.