Wordpress Plugin for DB query/ writing

Looking for someone to write a complete instruction/ teach me how:
(or even developing an own plugin)…

Looking for a plugin that fulfills the following tasks…

1. Connecting to an external Database

2. Query DB
Show Datas on a Wordpress-Page
Show selected Datas on Wordpress-Page
Count special table/ row/ number of datas
Show Datas via search query (search query on Wordpress-Page)
Show a picture from Wordpress-Server (Link given from external DB)
Show a video from Wordpress-Server (Link given from external DB)

3. Make entries in Database (only for registered Users on Wordpress)
Upload picture/ video
I saw a possibility to realize all this via a php-plugin?
Myself I don`t have much experience with plugin but could work this out by myself if someone shows me the way
No matter how the solution might be it has to be safe so none may see or get the db-connection-datas