What're the most valuable skills that can be learned within 6 months?

[bored]

What hard or specialized skills are in high demand with competitive pricing that can be learned in less than 6 months? Assuming the individual has at least above average intelligence.

If the topic is broad like "programming" try being more specific with subtopics like "front-end development with XYZ frameworks".

[walshemj]

If you don't all ready know it having a good understanding of SQL.

Even a high quality 1 week intro course.