fenway

I don't follow what's desired here.

This is a very serious concern -- and in general, a true "rollback" is all but impossible.

Then, solved?

Not even necessary -- you have the ID already!

I don't see any reference to item comments in your query.

You'll need to check the value for Col2 across all rows before you write the CSV.

But wouldn't I have to make a seperate row for each and every relation between product and accessory? Indeed.

Yes there is -- as you check each row in order.

I'm not sure I follow -- just limit your export.

I'm not sure I follow -- if you're issuing the update statement, then you know which fields were changed...?

What's wrong with BETWEEN?

A few user variables should do the trick -- update one whenever Col1 changes, increment the other when it doesn't.

Did the JOIN not work?

That requires joining the table to itself as many times as you has Qs.

It's not that it lacks anything, per se -- just that the default mix on HTML and scripting blurs the line for new programmers, and then they never completely recover.

I'll resist the temptation to argue -- but I agree that the problem is that it's too easy to learn.

The real problem is that PHP is the worst possible language to start with to learn that separation, specifically because it's a glorified template.

Let's not even entertain such an idea. The whole purpose of the separation is to force the OP to decide exactly which aspect is causing the problem -- and this also helps people resist the urge to post entire scripts.

Covers: Part 1: Using the MySQL Improved Extension, mysqli Part 2: Using the MySQL Extension, mysql Part 3: Using the PDO Extension With MySQL Driver, pdo_mysql Part 4: Using the MySQL Native Driver for PHP, mysqlnd Tutorial is here.

Well, a scalar subquery, that is.

Hopefully this presentation will stay online at scribd... it's simply fantastic, probably the best I've come across in recent memory. At 220 slides, it's quite lengthy -- but the lessons learned are invaluable, so be sure to read all the way to the end. A MUST READ!!!! EDIT: This year's version of the presentation -- some really great stuff in here, particuarly about hierarchies.

At the 2008 MySQL Conference and Expo, The Pythian Group gave away EXPLAIN cheatsheets (PDF).

This resource covers a very broad range of topics... it's worth a look, though, especially if you're stumbling in the early stages of configuration.

Basically, this blog contains a regularly-updated run-down of MySQL functions, with a short description and a few hints on how to use them; RSS feed here.

Please read the excellent FAQ thread on this issue by our very own wildteen88.