How to understand the short SQL in Oracle and MySQL

This article will explain in detail how to understand the short SQL in Oracle and MySQL. The content of the article is of high quality, so the editor will share it for you as a reference. I hope you will have some understanding of the relevant knowledge after reading this article.

If you were asked to write a simple and awesome SQL, regardless of the database type, what kind of SQL statement would you write?

Oracle

If it's Oracle, I'll write a drop table dual.

This SQL looks very simple, contains a large amount of information, first of all, you have to have some understanding and understanding of the dual table, and this view is different from the general data dictionary, if deleted, it will directly lead to the database unavailable. Recovery requires an implicit parameter to adjust.

Of course, if you want to write some SQL with philosophy of life from a different point of view, it will take a lot of work.

I thought of one, such as Flashback database to sysdate-1/24/60.

What I'm trying to say is that the database can flash back to a minute ago, and our lives won't, none of them.

MySQL

I really thought a lot about writing a few SQL in this respect from the perspective of MySQL, but I didn't feel very satisfied until I saw a MySQL performance test statement provided by jeremycole, which was simple but powerful.

Https://github.com/jeremycole/yesmark can be seen on github

Statement on one line:

Yes "DO 0;" | mysql > / dev/null &

If you want to open a parallel, that's not a problem, such as 16 concurrency.

For i in {1... 16}; do yes "DO 0;" | mysql > / dev/null & done

Such sentences are really short and concise.

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