Summary of SQL Overview

So talk about SQL today, structured query language. Basically, it's database. When you go today to any website like Facebook, Instagram, TikTok, whatever you use today, or even desktop applications, it's very likely it is using a database to store all the information that you see. For example, when you fill your profile, you have your name, right? You have some links, you have your description. Where does that information go? Well, ultimately, it goes behind the scenes to a database, and that's where it is stored so that next time you access the website, it remembers all of that. So the most popular way of storing data is via SQL. It's like a database. We write in this language called SQL or SQL, and a structured query language. So you can think of this as like Excel. Let me share my Excel. So it's like except you ever use Microsoft Excel or Google Sheets or whatever spreadsheet software, you have rows and columns, right? So in SQL, basically, we're gonna have what we call tables, and each table has columns and rows. So the columns, they denote what kind of information. For example, I wanna store the first name of somebody. I can say here first name, right? So I have a lot of people, I can have John, I can have Maria, et cetera, right? So the heading here would be what we call column for this table. And then we have each row, right? The first row is for a specific person. The second row for another person, and Excel goes on. So every row represents a different object or a person in this case. So when we go back to programies, what we're gonna see is on the right-hand side, you see all your available tables for this exercise. So we have a table of customers, and as you can see, we have some columns. And then each row represents a person or a customer in this case. So we got information about the first name, last name, age, and then the person's country. Now, what we typically do with SQL is we always have ID column to identify each row. And it typically is sequential, starting from one, and then a new one would be two, and so on. So it's very common, it's a way of uniquely identify that record. So we have a table of orders that's just for orders. Okay, somebody ordered a keyboard, paid 400 bucks, and it tells you which customer. In this case, it goes by ID. So if you say customer ID four, it means you gotta go to the customer's table and see, okay, the person who has ID four is the one that bought this keyboard. And then we got shipping. So this is all about shipping. You can see shipping of ID one, status still pending, and the customer is number two. So number two, okay, I gotta go to the customer's table and look up who is customer number two, that's Robert Luna. So as you can see, each table kind of represents a specific piece of information. You cannot have everything together that are not related. So we separate the customers, we separate the orders and shippings, and if you need to find information across all of those tables, you gotta look them up. Like they have it here, like, okay, the customer four. So you gotta always look up in the customer's table who that is. Okay, so we got tables and tables have rows and they have columns. So in SQL, we make what's called a query to ask about information. So in this editor here, you can write a query and then you can click run SQL and that will run the query and do whatever command you wish you did that. Okay, so today we have different kinds of flavors of SQL. SQL is a general term to the structure query language, but many companies have implemented their own version. For example, you might have heard of MySQL or Microsoft SQL Server or Oracle SQL, so IBM SQL and so on. Every company kind of make their own version, but it's all ultimately the same standard language. If you learn how to write SQL standard, you will probably, you will understand how to write a query from any of those flavors.