unique int id for a certain category in mysql

So the db str开发者_Go百科ucture looks like this

tablename(uniqueid, categoryname, categoryid)

I want to be able to generate a number that would be unique where categoryname="something"

Example, I can have the categoryname as 'something', and there are 5 different rows with the categoryid 1,2,3,4,5. and another categoryname as 'somethingelse', and there are 3 different rows categoryid of 1,2,3.

Since auto_increment wouldn't work, i was wondering if I can do that via php?

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No, you just need to get auto-increment to work, are you sure that the uniqueid column is set as the primary key?

Also, why do you have both uniqueid and categoryid?

For example, your table creation query should have looked something like this:

CREATE TABLE categories (
    id INT NOT NULL AUTO_INCREMENT,
    name VARCHAR(255) NOT NULL,
    PRIMARY KEY (id)
);

auto-increment can only be set on the primary key of the database table and it can only be set on one column.

there is much more info about auto-increment in the MySQL doc: http://dev.mysql.com/doc/refman/5.0/en/example-auto-increment.html