Basic Select 4 Beginner

I am looking desperately for some docs or anything on how to write a basic function to return a single value back to the page. For example, “select First_Name,Last_name….” for a single poster. I am very familiar with databases/SQL and know enough php to get in trouble. I can not seem to get this basic step done when in the wordpress env….Can anyone point a frustrated beginner to a tutorial on doing your own retrieving from the database. I promise I have looked…but have only found pieces or how to install a table for a plugin. I can install a table. I just can not pull my data out correctly yet. Thanks in advance to any responders.

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