MySQL: making a column unique?

Question

I have a table that is in production. I realize that some of the columns should be unique. Is it safe to go into phpMyAdmin and change those columns to make it unique?

ALTER TABLE  `foo` ADD UNIQUE ( `bar` )

Answer 1

Follow the below steps to apply unique column value from phpmyadmin panel:

Go to the table structure. Click on the unique keyword as like below -

Click on the ok from confirmation box -

Unique value constraint for column will apply. Or you can run mysql query:

ALTER TABLE user ADD UNIQUE(email);