Which SQL database is most in demand? Best one to match with JavaScript?

[Jimkooper]

Hey everyone,
I currently only know mongodb / mongoose and I feel like I have a huge hole in my existence not knowing SQL. It seems almost all jobs I look at require SQL experience of some sort. I actually just got off a phone screening and the guy basically told me all they use is SQL so I am out of luck.

I was wondering which SQL database should I learn to pair with javascript?
[color=#333333]revs check qld[/color]
PostgreSQL? Oracle? MySQL?

I would appreciate it if someone could also answer: If I learn one of them, does that mean I know all of them? SQL is Structured Query Language yes? So does that mean knowing one, I know all of them?

And which one is the most hot and in demand one in the job market?

[highrise]

Hey, let me answer your last question first.
No, you don't, but you probably can learn the others pretty fast. SQL is standard essentially but all of the RDBMS have added some functionality where developers found this missing from the standard. So most of the simple queries are the same, but all have slight deviations and/or additions or maybe even have not fully implemented the standard.

Coming from JavaScript you can consider SQL a standard like HTML , CSS or JS, but looking at different browsers you find their individual differences as well.

Asking for JS in the context of Database I assume you are talking Serverside (like nodeJS) here?

The biggest difference to mongo when using SQL is that your data needs to be structured. You are working with tables (or potentially objects when talking about PostgreSQL) instead of documents.

PostgreSQL and MySQL are both good startingpoints.