describe guestbook

describe ol_user userid 

describe guestbook id

{DESCRIBE | DESC} tbl_name [col_name | wild]

mysql> desc ol_user username\G

*************************** 1. row ***************************
 Field: UserName
  Type: varchar(100)
  Null: NO
  Key: MUL
Default:
 Extra:
1 row in set (0.02 sec) 

mysql_connect('localhost', 'root', 'root');
mysql_select_db('demo');
$test = mysql_query('Describe cdb_posts first');
$test = mysql_fetch_array($test);