Question

I have about 1 million data in users table.

Now I want each user can have multiple colors their like.

Example user_id = 1 like color blue, green, yellow, black etc. So here what is the good database structure to store this color value?

Answer 1

If each user can have any number of colors, then you should create another table, something like this:

CREATE TABLE userColors (
    userID INT,
    color VARCHAR(16),
    FOREIGN KEY (userID) REFERENCES users(user_id)
);

Then each user can have any number of colors, so if a user has three colors associated with them, they will have three entries in the userColors table.