SQL Journey: Blog #12

What's up Nixers! After finishing the Power BI tutorial by Alex the Analyst, I decided to embark on learning SQL once again. A sort of a review of what I have already learned in Khan Academy. I am already in 5 of the 17 videos in this playlist.

The reason why I decided on this next step is to test my knowledge of SQL following what I have learned in Khan Academy. I thought to myself that if I can use my SQL skills to do what he instructs before looking at the code he uses, then I will have better confidence moving forward. If not, I will have a serious look at what I lack and improve on those things.

The things that I noticed is that Alex uses SQL Server Management Studio (SSMS) while Khan Academy uses SQLlite.js. I learned the difference the hard way as I committed errors in the codes that I used. In SQLlite, the use of 'TEXT' as a data type was now changed to 'varchar(size)' is prevalently used in SQLServer. Also, when assigning values, the use of single-quotation marks when the data type is varchar is also prevalent. Like, a syntax error will result if the double quotation marks is used.

Alex also explained INNER JOIN, LEFT OUTER JOIN, RIGHT OUTER JOIN, and FULL OUTER JOIN more clearly. Here's what I learned big time. Whenever "JOIN" is used, there must ALWAYS be an "ON" statement. I don't know if this is just a small thing but for me this is a big deal considering I sometimes forget the syntax so having this mnemonic or understanding would go a long way.

I also do not use copy and paste of codes. I type codes manually for me to familiarize my self with the syntaxes. Another thing that I made sure to find a way about is how to show the "line" relating to a code, so that I can easily trace the error when it prompts. Next, I used SQLShades to activate DARK mode when coding. It is more eye-friendly and fit for my preference since I also use dark mode in Pycharm.

Whew! 12 more lessons to go.

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