SQL Beginner's Tutorial: Writing your First Queries

Hey Friends!!

Thanks for coming back!

An example of the complexity of the Relationships between some tables in a Database

I know the first tutorial was busy, this one will be as well!! We will be busy here as well, but I hope we can have some fun. I know I plan on having some fun.

So let's begin...

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SQL is a bunch of CRUD

Yeah, you heard me. CRUD! Not the way you think, though.

CRUD in Database Management means a great deal, even though the word itself doesn't sound like a word you'd want to use. In fact, it's a shortening of the words (C)reate, (R)ead, (U)pdate & (D)elete. C-R-U-D. The statements identify the major components of Database Management and tells the database what to do and how.

A Create statement tells the Database System to, literally, create something. Whether you are looking to create a table, a database, a View, or something else, the Create statement allows the system to do just that.

You Read data from tables. this is one basic way to interact with the Database information.

An Update statement tells the Database System to update data in a Database Table. This statement allows the system to change data in the table that is already in place. eg. if you are saving High Scores for a game, the Update statement will do just that.

A Delete statement is fairly self-explanatory. It removes rows from a Database Table.

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Queries and its Parts

As I said earlier, a Query is a Question that you ask a Database (or set of Databases) in order to find an answer in the form of columnized rows (as in a spreadsheet). Within that Query are components

Statement - what do you want to find?
From - what table do you want to look in?
Join - do you need to join together multiple tables?
Filter - how do you want to filter the data?
Grouping - how do you want to group the results?
Sorting - what order do you want to sort by?
Having Filter - do you have any extra filters to use?

I don't have a great deal of time to finish this post, so I'm going to cut it short. The next tutorial will elaborate on the Query itself and how to begin thinking about building the query.

Thanks for reading!!

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