3 replies to this topic

[hetra]

Hello all,

I'm finishing off my blog commenting system on my website. I want the comment to be posted with a cid (Comment IDentification). Basically, when I try and make in AUTO_INCREMENT in PHPMyAdmin, it says:

#1075 - Incorrect table definition; there can be only one auto column and it must be defined as a key

I would try to do it in PHP by adding one to the result of

SELECT COUNT(*) FROM comments

but it would fail as it's an associative array.

Thanks.

[RhetoricalRuvim]

What about this?:

SELECT MAX(cid)+1 FROM ...

Or this?:

INSERT INTO table_name (id, cid, comment_text) SELECT MAX(id)+1, MAX(cid)+1, 'the text for the comment...' FROM table_name 

The latter is similar to what I actually used for a website, for registering users.

[hetra]

Thanks, the latter one did work fine. I don't usually pry into that much SQL syntax so thanks for the help.

[Orjan]

Sorry, but I don't understand the difference between the id and the cid column in this table, as they seem to get the same value on all rows if you start with an empty table... why not just auto-increment the cid and skip the id column?