MySQL: using random function in existing table for generating derived column

Question

i have a table 'product' with column 'category' which consists of 10 different categories without a column category_id. i want to derive a table with new column category_id for each category.

select product_id,description,category, round(rand(10)) as category_id from product;
select product_id,description,category, rand( over partition by 10) from product; 

using above query i have tried "round(rand())" however this gives only 0 and 1, but i want it to allocate category_id for 10 products from 1 to 10.

Also i want to retrieve the products from two random category

Answer 1

Use FLOOR(1+ rand() * 10) this will give you a number between 1 and 10

select product_id,description,category,FLOOR(1+ rand() * 10) as category_id from product;