this tut will teach you how how to sql inject via cookie [also known as 'session based' or 'cookie parameter'].

until now,we know about two methods:
get - via url*.php?id=1 union select ....
for example
post - via box
like this one
code: (in the search box)

and now,we gonna learn cookie.
lets strat:
first,you need google chrome.

after you have downloaded,download the addon "cookie editor" from philip.
click "+ add to chrome"

first,thanks to hooded robin,that gave me the site for testing.thanks man.

now after we downloaded chrome and cookie editor,lets strat for real-
get in vuln site.
for example-
not id=1 or search box. lets do it with cookie sqli.
click the cookie editor sign

and add ' to the value "sessid"

and hit sumbit.

for advanced-
we can learn from the error:
-one n.o.columns
-mq off
-full path /home/americas/public_html/admin/
for beginners-
lets try finding n.o.columns (number of columns) with group by.
click the cookie editor sign and write

' group by 2--+

unknown column '2' in 'group statement'

' union select 1 and 'a'='a

(the 'a'='a part is for closing a string)
notice: we cant use union here cause the query get inside a "insert into" query..but union will work on other site.
you can use 'and' for extract data (' and (select 1 from table)--+)