MAX function in MySQL??

I need to find the largest value of a field within a given table. For example, I have an AUTO_INCREMENT column, and I need to find the largest value... How do you do that? sorry if this is an ignorant question...

Just select the field, sort it and take the first row at the top.

SELECT field
FROM table
ORDER BY field DESC
LIMIT 1

I have a question: which way is better to find the max: using limit and order by, or using MAX?

*Is* there a MAX function?

Use limit and order_by. max() should be used if you want to return several max values. For example, let's say you have a table with products that has the product_id, a category_id and price. You need to find the most expensive product in each category. You could do this:

select product_id,category_id,max(price) as m_price from products group by category_id order by category_id;

This would return the most expensive product for each category.