That means #1 is totally relational (as an aside, you don't need ORDER BY or LIMIT for it either).
I would love to see it. Yes, you can do it in SQL, but I'd say it's not easy at all without ORDER BY and LIMIT or windowing functions and I don't know if you can do it in Tutorial D. For the reference, #1 is:
Show the blog post with the largest number of comments. If more than one exist, pick the latest.
The schema is:
post(id integer, created timestamp)
comment(id integer, post_id integer)
See CJ Date's excellent discussion on ORDER(BY)
I read it and the book as well, but I wouldn't call it excellent. What I read there is a reluctant admission of failure to incorporate an important operation to his query model. I see no attempt to analyze why it doesn't work or adapt the query model to make ORDER a regular operation.
I would love to see it. Yes, you can do it in SQL, but I'd say it's not easy at all without ORDER BY and LIMIT or windowing functions and I don't know if you can do it in Tutorial D. For the reference, #1 is:
Show the blog post with the largest number of comments. If more than one exist, pick the latest.
The schema is:
See CJ Date's excellent discussion on ORDER(BY)I read it and the book as well, but I wouldn't call it excellent. What I read there is a reluctant admission of failure to incorporate an important operation to his query model. I see no attempt to analyze why it doesn't work or adapt the query model to make ORDER a regular operation.