Best courses to revise SQL in 2 days?

[shivajikobardan]

TL;DR Summary

Learn SQL for customer support engineer intern

I am customer support engineer intern.
My supervisor has assignmed me to learn SQL in 2 days. I've studied mysql in the past as well.
https://www.w3schools.com/sql/
He has asked me to learn till SQL data types.
Are there any video courses to revise my sql using mysql? Remember that this is for customer support engineer job so I don't require very vast knowledge of SQL, there'll be DBAs for that.
I'm considering this course. Do tell me if I should buy it or not. This is by far the best course I've found.
https://www.udemy.com/course/practical-sql-masterclass-with-mysql/
My second preference is this course:
https://www.udemy.com/course/the-complete-sql-master-bootcamp-sql-database-beginner-to-mysql-expert/
Tell me which one should I buy? None? If None, which?

 

[Wrichik Basu]

YouTube is your friend. Just search something like "SQL Crash Course" and you will see videos that are from 60 mins to 4 hrs long. Good for revision, I believe. And while working, if you need the commands, just use w3schools.

 

[shivajikobardan]

I find youtube tutorials to be of very low quality (of teaching) not sure why. I used to use them a lot in the past. They just illude me that I'm learning something. I may be wrong.

 

[Wrichik Basu]

You can use https://www.w3schools.com/sql/ to brush up the forgotten commands. And you can also go back to your past homework.

 

[shivajikobardan]

If I were to use a site I'd recommend sqlbolt.com and sqlzoo.net. I learnt from them at that time. Now, when I look at them, I feel empty. I don't get anything.

 

[BWV]

If you have MS Access, use the query builder gui then convert to SQL to get some intuition on the language

 

[jack action]

The following is a repost of this post with updated links:

I really like the MySQL documentation.

The problem with other sources is that they show you some very basic stuff. But SQL is full of very useful things that are needed, especially with very large tables. So the documentation is quite heavy, but in the end, you'll find that it is necessary to understand it fully to do good table structures and efficient data manipulations.

I would suggest you start with the following chapters (in order), such that you don't get lost or bored too much. For most of the important stuff elsewhere, there is probably a link inside those sections to reach it. I would also focus on the innoDB engine first, as it is probably the one you'll use (although, I'm not bashing other engines).

Chapter 9 Language Structure

This chapter explains the basic language structure. Pretty simple stuff if you are used to programming.

Chapter 11 Data Types

This chapter is essential to help you choose the proper data type (i.e. the one that takes less storage space). Focus mostly on numeric and string types at first.

Chapter 13 SQL Statements

This is what I consider the tutorial part of the documentation, especially the first two sections:

• 13.1 Data Definition Statements
• 13.2 Data Manipulation Statements

Section 13.8.2 is also essential to understand to learn how to build good queries.

Chapter 12 Functions and Operators

For when you'll want to do more complex comparisons or string manipulations.

Finally, I also suggest Rick's Rules of Thumb which helped me a lot understand the art and importance of proper SQL.