PHP PDO Query

I'm looking for someone to create a PHP PDO, query I already have the pdo dbconnect file which will be provided if you accept this job. All I need you to write is something to enable me to fetch all the data from a table and certain columns. E.g column1, column2, column4, column5.
Note it has to be PDO, not normal mysql statements.

The code you provide must be well commented so I can understand what does what.

Thanks