Emil Drkusic

Emil Drkusic
Latest posts by Emil Drkusic (see all)
join multiple tables - tables needed

Learn SQL: Join multiple tables

January 27, 2020 by

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.

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SQL - types of relations

Learn SQL: Types of relations

January 22, 2020 by

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).

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Learn SQL: SQL Scripts

January 21, 2020 by

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.

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Learn SQL: SELECT statement

January 13, 2020 by

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.

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Learn SQL: Foreign Key

January 7, 2020 by

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.

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Learn SQL: Primary Key

December 20, 2019 by

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.

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December 12, 2019 by

In the previous article, we’ve created two tables, and now we’re ready to use the SQL INSERT INTO TABLE command and populate these tables with data. In order to do so, we’ll prepare statements in Excel and then paste these statements into SQL Server and execute them. We’ll also check the contents of both tables before and after these commands using the SELECT statement. So, let’s start.

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