Alter table if field or column not exist

[milo_pantig]

Myscript should alter the table if the field or column not exists.

I try this but its not working.
fieldname = image

$DB->query("ALTER TABLE p17_sections ADD image VARCHAR( 24 ) NOT NULL AFTER sorting If not exists");

any help!

Thanks

[devinemke]

do a DESCRIBE query first to see if the column exits

[milo_pantig]

can u give me the exact php code please

im trying this
$DB->query("Describe table "); yes if the field not exist then it will alter the table then add the field name 'image' i dont know the exact php script please help thanks

[Roger_Ramjet]

read the manual