Syntax:
{DESCRIBE | DESC} tbl_name [col_name | wild]

DESCRIBE provides information about the columns in a table. It is a
shortcut for SHOW COLUMNS FROM. These statements also display
information for views. (See [HELP SHOW COLUMNS].)

col_name can be a column name, or a string containing the SQL "%" and
"_" wildcard characters to obtain output only for the columns with
names matching the string. There is no need to enclose the string
within quotes unless it contains spaces or other special characters.

mysql> DESCRIBE City;
+------------+----------+------+-----+---------+----------------+
| Field      | Type     | Null | Key | Default | Extra          |
+------------+----------+------+-----+---------+----------------+
| Id         | int(11)  | NO   | PRI | NULL    | auto_increment |
| Name       | char(35) | NO   |     |         |                |
| Country    | char(3)  | NO   | UNI |         |                |
| District   | char(20) | YES  | MUL |         |                |
| Population | int(11)  | NO   |     | 0       |                |
+------------+----------+------+-----+---------+----------------+
5 rows in set (0.00 sec)

The description for SHOW COLUMNS provides more information about the
output columns (see [HELP SHOW COLUMNS]).

URL: http://dev.mysql.com/doc/refman/5.1/en/describe.html

