How to learn SQL (step-by-step guide) in 2021

With the gradual shift in digital technology in recent years, trillions of bytes of data are being generated every second. It has been rightfully said by some of the experts that - “Data is the new oil!”. The data generated by the users come in various forms - these are generated through social media browsing, binge-watching movies, shopping through online portals, online banking transactions, etc.

So what’s the use of such large volumes of data? These data are organized as per the needs of companies to carry out targeted ads to attract customers to see and buy their products. This data is used to analyze the customer’s behavior to improve user experience to increase their sales or shoot up their service quality.

However, the generated data is highly unorganized and needs to be cleaned before the experts can analyze it. Also, storing such huge volumes of data is another big task to handle. Nowadays, several big data solutions help companies store, organize, and analyze large volumes of data. But what about the already structured data that comes from the websites. These include your login/signup details, credit card details, user-profile details, online purchasing history, etc. These data can be reused by the companies when you visit their website the next time. To reuse it, it’s obvious that they need to store it somewhere in a secured place.

Large server nodes are set up either on the cloud or physical machines with huge databases where such data is stored. Now, several types of databases can be used for different purposes. And to manage the different types of databases, one needs a certain set of database management skills. Let’s discuss the different types of databases first.

1. Hierarchical Database

This type of database has a tree structure where they have a parent node, and each parent node has several child nodes linked with branches. The parent nodes represent the higher-level data, and the child nodes represent the lower-level of information, and the branches represent the relationship between these nodes.

2. Object-Oriented Database

This type of database has key components such as classes and objects. Objects can be defined as real-time instances of the classes. They hold records or actual data to be stored. The classes have functions, methods, or variables that define the operations to be performed on these objects or data.

3. Network Database

This type of database has a network structure. It supported many-to-many relationships between the nodes and was designed to solve the problems with a hierarchical database.

4. Relational Database

In such databases, data is stored in records or tables whose columns define the type of data, and the rows contain the actual piece of information. Tables can form relationships with other tables based on conditions.

The most common type of database used across organizations to store data in an organized, secured, and robust manner is the relational database. Relational databases are highly scalable and flexible when it comes to accessing certain sets of information. SQL or Structured Query Language is a programming language used to query relational databases and find out records or information from the tables.

What is SQL?

As discussed earlier, SQL is a programming language that you can use to query data in relational databases. You can create, update, modify, delete, and perform other operations on the tables in relational databases. SQL is a declarative language, or in other words, it’s a procedural language. This means that the user can specify what type of data instead of specifying it and getting the data.

Problems with Traditional File System

Before the invention of SQL or other databases, data was stored in file systems with lots of uses related to data mismanagement. Even though we think that file systems look neatly organized, there are multiple flaws associated with them when storing, accessing, and modifying continuous volumes of data. Let’s discuss a few of them.

1. Redundancy of Data

Data redundancy means that the same information is stored in one or more places, leading to unnecessary storage space usage. In the case of file-based databases, there was no way to look out for duplicate files. Also, consequently, the file system becomes exposed to security hazards and information leaks.

2. Data Dependence

In file systems, there’s a specific structure that needs to be followed. If we change any record’s format, we need to update all the data formats dependent on it. Moreover, changes in the structure of file-system-based databases largely impact the performance of the applications.

3. Data Sharing

Sharing of data was a major issue in file systems as it would lead to major security risks. Even if we used security measures such as encrypting files, password-protecting them, locking out portions of it, etc., these measures are not robust enough to ensure complete security.

Due to all the above-mentioned reasons, there was a strong need to create a new form of data storage to address all these problems.

Importance of SQL

Let’s take a look at a few important points that made SQL such a popular querying language.

1. Popular Among Professionals 

It’s universally adopted experts, and professionals turn to SQL without a second thought when handling and organizing data. All the popular open-source and free databases support SQL to query information.

2. Easy to Learn

The syntax of SQL is similar to simple natural language and is quite easy to learn when compared to the complex syntaxes of other programming languages such as Java, C++, etc.

3.Handle Large Sets of Data

Compared to excel and spreadsheets, SQL can easily handle large datasets with minimal effort required to manage them.

4. Better Insight Into The Datasets

To retrieve useful insights from data, you need to understand the data better. SQL allows you to use commands to obtain relationships between the datasets to understand them better.

5. Standardized 

SQL is a query language that both ISO and ANSI have standardized. It’s quite stable, with no big updates in syntax, and once you learn it, you don’t need to focus much on newer releases.

6. Hot Skill

Doesn’t matter if you want to work in data science, machine learning, database management, data analysis, etc., SQL is a common skill and has a great demand in the job market.

Why Should You Learn SQL in 2021?

Let’s skim through a few points that would allow you to understand why SQL is one of the most important skills to get your hands dirty on to stay up-to-date with the top skills and technologies.

1. It has lots of processing capabilities which are defined into sets such as Data Definition Language (create, alter, and delete schemas), Data Manipulation Language (update, insert, delete, retrieve tables), Data Control Language (revoke permissions or grant them).
2. It allows you to perform integrity-checking on the databases and normalize the databases to remove data redundancy and other problems related to file-system-based databases.
3. Just using a single line of command, you can retrieve highly filtered data along with multiple records.
4. Once you get handy with the language, you can use complicated queries to get better insights into the data.
5. It has an easy syntax, is highly scalable, provides high security, and has a large community.
6. It is interactive, highly portable, can create several views of a table to work and experiment on, and has a well-defined standard.

Career in SQL

Tons of jobs and careers require SQL as a skill in data-centric organizations. These organizations seek SQL professionals who can apply their analytical thinking with SQL to provide better insights on huge chunks of data. If you are a candidate who has a knack for working with data and manipulating it, you should definitely seek a career in SQL programming. The job market related to SQL can be found on cloud-based organizations and those who use databases on-premises.

Education Required

• Qualifications that the recruiters seek in an SQL professional may vary from company to company. It largely depends upon the ROI, client requirements, job type, etc.
• The basic educational qualifications include a bachelor’s or master’s degree in computer science engineering, IT, or even specialization courses in the IT domain.
• Additional certifications such as Database developer, administrator, designer, architect, etc., will add colors to your portfolio and grant you an upper hand over thousands of other candidates.
• Experience in PL/SQL, ETL, etc., would be beneficial.

Job Positions

• SQL Server stands as the 3rd most popular database server, and millions of professionals are currently working on different roles that directly or indirectly require SQL as a skill.
• Top career paths in SQL include - Database Administrator, Business Intelligence Professionals, Data Scientists, Database Developers, Database Testers, ETL Developers, BI Application Developers, Big Data Experts, Cloud Database Engineers, Database Migration Engineers, etc.

Salary

• The average salary of a SQL professional depends hugely on the career paths that he chooses. Usually, professionals with 5+ years of experience working with SQL have a higher average salary than freshers.
• According to a report by payscale in 2018, the average salaries for SQL developers in the US is around USD 65k, for Senior SQL Developers is USD 85k, for Senior Database Administrators, it is around $100k, for production DBA, the average salary can be as high as $130k.

Prerequisites to Learn SQL

To start learning a query language like SQL, you must know the following areas.

• Database Management Systems.
• DBMS concepts like normalization, ACID properties, transactions, etc.
• ER diagrams, relational models, and all about relational databases.

Apart from this, one should have good analytical skills and understand storing data in organized relational databases to generate useful insights from complicated queries through SQL.

Please note that even if you don’t have a background in Computer Science or IT and don’t have prior knowledge of Database Management Systems, you don’t need to worry. We will provide you with all the resources, courses, tutorials, and documentation that you will need to learn the concepts right from basic to advanced level later on in this article. So, please stick with us till the end.

How to Install SQL?

Let’s see how to install SQL Server in your Windows machine that will help you to write SQL queries such as creating databases, tables, inserting data inside tables, modifying and updating the data, etc.

You can download Microsoft SQL Server from the official Microsoft Website.

The latest version currently is SQL Server 2019. Please note that Microsoft allows you to download two free editions of the SQL Server. They are Developer and Express editions. The MS SQL Server Developer Edition has all the required features, but the problem with that is we can’t use it for production. However, the other free edition called MS SQL Server Express edition can be used for production but has limited features. For those who want to learn SQL, it is best, to begin with, the developer edition.

Press the Download Now button. This will download an executable file that you can run to install the SQL Server. Once the installation has started, it will ask you to choose one from three different types of installation - Basic, Custom, and Download Media. The Basic option automatically chooses all the basic packages that you will need to start working with SQL Server. The Custom option will allow you to choose your own packages, and the Download Media option will allow you to download all the packages and later install them on a different machine.

We will choose the basic option. After that, accept all the licensing agreements, choose the install location, and install the Server. After it has been successfully installed, you can click on the Connect Now button to start executing your queries.

IDEs for SQL

An IDE or Integrated Development Environment is a graphical tool that allows you to manage all your application-related files and work with useful packages, auto-complete features, syntax-highlighter, etc., to make your development experience better.

While it’s true that you can create and manage databases and tables right from the Command Line itself, using an IDE will always be helpful to get a birds-eye view of all the databases, queries, tables, and other components. In fact, some IDEs have a help section to explain to you the basic commands and their uses. You can just fill the text fields, choose the various pre-formatted commands, click on the Ok button, and your work will be done. It’s as simple as that. Moreover, some IDEs allow you to backup and restore databases and tables as well.

Hence, it’s always a wise decision to select an IDE that caters to your requirements before you get your hands dirty with SQL. Here’s a list of top IDEs that you can utilize to compose complicated SQL queries.