3.6.5. Using User-Defined Variables
You can employ MySQL user variables to remember results without
having to store them in temporary variables in the client. (See
Section 9.3, “User-Defined Variables”.)
For example, to find the articles with the highest and lowest
price you can do this:
mysql> SELECT @min_price:=MIN(price),@max_price:=MAX(price) FROM shop;
mysql> SELECT * FROM shop WHERE price=@min_price OR price=@max_price;
+---------+--------+-------+
| article | dealer | price |
+---------+--------+-------+
| 0003 | D | 1.25 |
| 0004 | D | 19.95 |
+---------+--------+-------+
