You did it!
Congratulations, you are well on your way to being an expert at SQL and PostgreSQL. Some final thoughts for you on what you learned today.
- Most of what you learned today is applicable to _any SQL database: MySQL, Oracle, SQLite, Microsoft SQL Server, etc. SQL is a general spec that all of these database then take and put their own flavor on. Many of these queries will work as-is on a different database. The rest have to be tweaked slightly to fit the other database's flavor. But all the principles you learned apply.
- This course focused exclusively on how to query a database and was generally focused from a programmer's perspective and not an operations perspective. Notice we didn't talk about replication, configuring a server, deploying, backing up, replication, etc. This is a course for another time (and another teacher!) This was to teach you about basic querying skills.
- We also didn't cover ORMs for Node.js. In general I've had more problems then time saved with using ORMs. I always want to have access to the underlying SQL at the end of the day. I normally need that control.
We also did not talk a lot about execution order of queries whereas lots of other courses do talk about it. Why? When I learned SQL for the first time I found it very confusing and I focused a lot on it when in reality 90% of the time it doesn't actually matter. Do you care if a INNER JOIN or a WHERE happens first? Normally no! Hence I left it out and as an exercise to you to explore more if you want to delve into it. Suffice to say, queries break down into a plan from PostgreSQL and then are executed in a particular order. In general you don't have to care. Only time we cared is with WHERE vs HAVING where HAVING has to happen last. [See this blog post][post] to have a more comprehensive overview.
Great job again! I hope you enjoyed the course! Please tweet at me what you thought and give this repo a star!
