How to count each genre stored in 3 different columns?

I have a home movie database, scraped from IMDB. The genres of the movies are stored in 3 separate columns (some movies only have 1, so the other two are NULL, while others have all 3 occupied).

For example:

Extraordinary Measures	2010	6.4	106	Drama		                Drama	NULL	NULL
Away We Go	        2009	7	98	Adventure, Comedy, Drama	Adventure Comedy Drama
Repo Men	        2010	6.3	111	Action, Sci-Fi, Thriller	Action	 Sci-Fi	 Thriller
The Ides of March	2011	7.1	101	Drama, Thriller	                Drama	 Thriller	NULL

I want to create a visual in Tableau showing the number of movies from each genre I have from each year.

I was wondering how I could create a query which would return the number of each genre.

I tried using GROUP BY, and COUNT.

Also I was thinking about using CASE but I feel like it'd be really complicated and hard to keep track of, so is there some built-in function to help me with my issue?

Thank you!

This can be accomplished by combining all genre columns into one column using union all and then applying the aggregate function count() to the resulting dataset:

select year, genre, count(1)
from (
  select year, genre1 as genre
  from mytable
  union all
  select year, genre2
  from mytable
  union all
  select year, genre3
  from mytable
) as s
where genre is not null
group by year, genre