PHP Return SQL field according to row number (not row ID)

Hi,
I am new to php/mysql, and am trying to output some data from a table using PHP.

In the table, each row has an ID, and a category.

I have the following query:

SELECT * FROM questions where sectionId = ".$sectionid."

Code (markup):

$sectionid = 1, or whatever value specified.

I then have another bit of PHP code that generates a random number.

I want to count down the number of rows specified, and return the values from that row. For example, I will echo the question, and later check the answer given against the correct answer.

It is for a quiz that will have multiple categories.

I hope that it is clear enough what I want - does anyone know how to do that?

Regards,
TAJ

EDIT: I am using PHP/MYSQL, so maybe there is a better way of making the SQL query to do so - I don't mind how it's achieved as long as I understand it! I really want to keep all the questions from all the categories in one table though

 

The problem I was having was trying to "count down" to a certain row (e.g. row 3 from the results) and output the data.

I've just come up with what I think is working, however. It's a completely different way, as follows:

1) Get the id of all rows matching the criteria (mysqli_fetch_array)
2) shuffle the array (shuffle($array))
3) take the first ids from the array, up to the number I need.

It seems to be working thus far, and a lot easier than what I was trying (I don't know if it is possible to count down the results?)