Fatal error: Call to undefined method mysqli::error() [duplicate]

Answer 1

My bad, there shouldn't be quotes in the sql statements for column fields. Now it works!

Answer 2

For those who stumbled on this page.

The error you get from

Fatal error: Call to undefined method mysqli::error()

This is because we need to access the error as variable not as function

so the correct code is

if(! empty( $mysqli->error ) ){
   echo $mysqli->error;  // <- this is not a function call error()
}

Hope this helps someone.