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Is there a less repetitive, more elegant way to write this SQL query?
I'm working on the Querying Relational Databases Course, and I'm on the exercise that reads:
-- Generate a report that lists the book titles from both [library] locations and count the total number of books with the same title.
My answer was:
SELECT title, COUNT(title) FROM ( SELECT title, COUNT(title) FROM books_north GROUP BY title UNION ALL SELECT title, COUNT(title) FROM books_south GROUP BY title ) GROUP BY title;
It seems to work (hurrah), but I feel like I'm missing some better, more efficient way to accomplish this task. Any suggestions? Or am I just being too picky?
Thanks for any suggestions you can provide.
Andrew Winkler37,739 Points
It looks like you're duplicating the GROUP BY and COUNT() fuctions superfluously. Additionally I like to separate things out by putting subqueries on new lines. It works the same.
SELECT title, COUNT(*) AS num FROM ( SELECT title FROM books_north UNION ALL SELECT title FROM books_south) GROUP BY title;