Today, data is the basis of any business. The world of enterprise computing is the epitome of data-driven businesses. The importance of structured storage of data is unquestionably in the focus. And at this time, with the computing model quickly shifting towards the cloud, and storage costs falling rapidly, enterprises are leveraging data more and more to tune their businesses.

SQL has many cool features and aggregate functions are definitely one of these features, actually functions. While they are not specific to SQL, they are used often. They are part of the SELECT statement, and this allows us to have all benefits of SELECT (joining tables, filtering only rows and columns we need), combined with the power of these functions.

SQL join multiple tables is one of the most popular types of statements executed while handling relational databases. As known, there are five types of join operations: Inner, Left, Right, Full and Cross joins.

If you want to get something meaningful out of data, you’ll almost always need to join multiple tables. In this article, we’ll show how to do that using different types of joins. To achieve that, we’ll combine INNER JOINs and LEFT JOINs. So, let’s start.

One of the most important things in databases is to understand the types of relations in the databases. That stands for both – a process of designing a database model as well as when you’re analyzing your data. Understanding these relations is somehow natural and not so complex but is still essential in the database theory (and practice).

I can hardly imagine making any complex database changes without using SQL scripts. We actually used them in this series so far, but we haven’t pointed out what they actually are. Today we’ll stand up against that injustice. Sit back, relax, and get ready to learn something new and useful.

INNER JOIN vs LEFT JOIN, that is the question. Today, we’ll briefly explain how both of these two join types are used and what is the difference. We’ll go through this topic again later when we’ll expand our model and be able to write much more complex queries.

The SELECT statement is probably the most important SQL command. It’s used to return results from our database(s) and no matter how easy that could sound, it could be really very complex. In this article, we’ll give an intro to the SELECT statement and we’ll cover more complex stuff in the upcoming articles.

In the previous article, we talked about the primary key (PK). In this one, we’ll check what is the foreign key (FK) and how it’s related to the primary key. This is the final step, after creating tables, inserting data, and defining primary keys, to cover all basics related to the database theory. There is much, much more than this, but if you understand these concepts, everything else is just expanding your knowledge around these basics.

If you’ve already worked with databases, then you could hardly miss the term – Primary Key (PK). And if you’re reading this series and use it to learn about databases, well, this article should give you a good overview of what the PK really is. Still, if you’re a database expert, maybe you’ll find something new or just refresh your knowledge. So, sit back, relax, and let’s dive into PKs.