mysql - I want to alter table in php , but my code is not working -

i want add column table using php code not working

$sql="alter table user_preference_table add column '$tag_id' varchar(60) "; $result = $conn->query($sql);

i think problem way of declaring variable query ?

is query right?

'$tag_id'

it variable contains id 501

replace single quote backtick.

$sql="alter table user_preference_table add column `$tag_id` varchar(60) ";

signle quotes inserting values database tables.

backticks used db fields.

they prevent errors of using reserved keywords in mysql.

e.g.

as  ...etc

Hide