Need Wordpress guru to fix MySQL issue

Got myself in a tangle and need a Wordpress expert.

Job is probably simple for someone who knows exactly what they're doing.

Essentially, I have a new Wordpress installation and I need to retrieve content (posts, comments, etc) from an existing MYSqL database and get them displaying on the new site.

I've connected Wordpress to the Database successfully but the content isn't displaying so I'm now out of answers.

Successful candidate will be offered lots of future work as have many clients running Wordpress.