Documentation Home
MySQL 5.7 Reference Manual
Related Documentation Download this Manual
PDF (US Ltr) - 35.4Mb
PDF (A4) - 35.4Mb
PDF (RPM) - 34.5Mb
EPUB - 8.7Mb
HTML Download (TGZ) - 8.5Mb
HTML Download (Zip) - 8.5Mb
HTML Download (RPM) - 7.3Mb
Eclipse Doc Plugin (TGZ) - 9.3Mb
Eclipse Doc Plugin (Zip) - 11.5Mb
Man Pages (TGZ) - 201.5Kb
Man Pages (Zip) - 306.8Kb
Info (Gzip) - 3.3Mb
Info (Zip) - 3.3Mb
Excerpts from this Manual

MySQL 5.7 Reference Manual  /  ...  /  Using User-Defined Variables

4.6.5 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 10.4, “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 |
+---------+--------+-------+
Note

It is also possible to store the name of a database object such as a table or a column in a user variable and then to use this variable in an SQL statement; however, this requires the use of a prepared statement. See Section 14.5, “SQL Syntax for Prepared Statements”, for more information.


User Comments
  Posted by Daniel on September 30, 2005
Remember that using user variables the query will not be cached if you use the query caching option on the server, and therefore the answer could be slower than what we might expect.

Sign Up Login You must be logged in to post a comment.