How do I specify unique constraint for multiple columns in MySQL

Question

I have a table:

table votes (
    id,
    user,
    email,
    address,
    primary key(id),
);

Now I want to make the columns user, email, address unique (together).

How do I do this in MySql?

Answer 1

Hello @kartik,

Use this:

ALTER TABLE `votes` ADD UNIQUE `unique_index`(`user`, `email`, `address`);

Hope it helps!!
Thank you!!