Is it possible to create mutiple MySQL queries within the same table?

Question

Is it possible to make multiple queries at once within the same query?

Here is an example of what I'm trying to do.

We have the following table:

| userid | price | stock | description | 
----------------------------------------
  1        10.00   5       some text 
  2        25.00   2       some text
  3        15.00   3       some text
  4        35.00   2       some text
  5        30.00   4       some text

The queries that I'm trying to do are:

1. the MIN and MAX price group by description
2. the price set by userid 2
3. Stock and price of the first three results only without grouping

So the HTML table will look like this:

description | Min_Price | Max_Price | Price Set by userid 2 | 1st Price | 1st Stock | 2nd Price | 2nd Stock | 3rd Price | 3rd Stock

Answer 1

MySQL Unions (http://dev.mysql.com/doc/refman/5.0/en/union.html) should probably put you on the right track.

You could also do most of it with sub selects, though that is probably not a great idea.

Answer 2

Use union or, to have everything in one row, something like that:

Select 
 (Select min(price) from table) as min_price, 
 (Select max(price) from table) as max_price,
 ....

Answer 3

This solution will require a number of "sub queries" or joins.

You are probably looking at something like:

select t1.description, 
       t1.min_price,
       t1.max_price,
       t2.user_id_2_price 
from
  (select description, min(price) as min_price, max(price) as max_price from t group by description) t1 
left join
  (select price, description as user_id_2_price from t where userid = '2') t2
on
  (t1.description = t2.description)

And you can add as many of these "left joins" as you need