SQL – An Overview

SQL – An Overview


A language used to manage databases, SQL allows for the construction, deletion, retrieval, modification, and other operations of databases. Although there are numerous variations of the SQL language, it is an ANSI (American National Standards Institute) standard language.

What Does the Term SQL Mean?

Structured Query Language is known as SQL.

The computer language SQL, or Structured Query Language, is used to store, manipulate, and retrieve data from relational databases.

The preferred language for Relational Database Systems is SQL. SQL is the common database language used by all Relational Database Management Systems (RDMS), including MySQL, MS Access, Oracle, Sybase, Informix, Postgres, and SQL Server.

In its simplest form, it’s a language that enables interaction with databases to manage all the data they hold.

Many web applications and mobile apps rely heavily on data. For instance, a user’s profile information, which includes information about their friends and posts, is stored in a program like Facebook. A database system is utilized to store this data. It is possible for programmers to work with the data thanks to the computer language SQL.

Additionally, they use several dialects, such as JET SQL (native format) for MS Access, PL/SQL for Oracle, T-SQL for MS SQL Server, etc.

Why SQL?

SQL is well-liked because it provides the following benefits:

  • Enables users to describe the data, define the data in a database, and manipulate that data. • Enables users to access data in relational database management systems.
  • Enables embedding within other languages utilizing pre-compilers, libraries, and SQL modules.
  • enables the creation and deletion of databases and tables by users.
  • Allows users to develop views, stored procedures, and functions in a database.
  • Allows users to establish permissions on tables, procedures, and views.

A Snippet of SQL’s History

1970 – The invention of relational databases is credited to Dr. Edgar F. “Ted” Codd of IBM. He discussed a relational database model.

Structured Query Language first debuted in 1974.

IBM attempted to develop Codd’s concepts and unveiled System/R in 1978.

The first relational database prototype was created by IBM in 1986 and was standardized by ANSI. Relational Software, which subsequently became known as Oracle, released the first relational database.

SQL Operation

For any RDBMS, the system decides how to best carry out your request when you execute a SQL command, and the SQL engine decides how to interpret the task.

This method consists of a number of elements.

These parts include things like the query dispatcher, optimization engines, classic query engines, SQL query engines, and others.

Logical files cannot be handled by a SQL query engine, only by a traditional query engine.

An easy-to-understand diagram of the SQL Architecture is provided below.

SQL Statements

CREATE, SELECT, INSERT, UPDATE, DELETE, and DROP are the common SQL commands used to communicate with relational databases. Based on the nature of these commands, the following categories can be made:

Data Definition Language Senior Number

Instructions & Description

Sr.No. Command & Description

Creates a new table, a view of a table, or other objects in the database.


Modifies an existing database object, such as a table.


Deletes an entire table, a view of a table, or other objects in the database.

DML – Data Manipulation Language

Sr.No. Command & Description

Retrieves certain records from one or more tables.


Creates a record.


Modifies records.


Deletes records.

DCL – Data Control Language

Sr.No. Command & Description

Gives a privilege to user.


Takes back privileges granted by the user.


The word SQL is typically pronounced similarly to the word sequel. As with gif vs. jif, it depends on personal preference; some people pronounce it as an acronym with all three letters, like “ess-que-el.”

A programming language, is SQL?

SQL is a type of programming language, yes. It provides looping, logic instructions, variables, and other features. It’s not a language in the same sense as something like Java or C++, though.

Java and C++ are third-generation languages, but SQL is regarded as a fourth-generation language (4GL) (3GLs).

SQL is a language for storing, accessing, and modifying data in databases rather than being a programming language for creating websites, apps, or software.

Background of SQL

The initial version of SQL was created by IBM researchers Raymond

Donald Chamberlin and Boyce. Its original name was SEQUEL (Structured English Query Language), and it was intended to be used with System R, IBM’s database management system, to edit and retrieve data.

The first SQL implementation to be made commercially available was developed by Relational Software, Inc. (now Oracle) in the late 1970s.

A common definition of SQL has been established by the American National Standards Institute (ANSI) and the International Organization for Standardization (ISO) in 1986.

Utilizing SQL

Databases are not set up to grasp languages like Python, PHP, or Ruby, even though an application may be programmed in one of these. Databases previously only understood sequel (though this has changed significantly in recent years).

Because of this, if you want to work in web development or app development, understanding SQL is practically a requirement.

SQL has its own markup, just like other programming languages. Because of this, before using SQL markup properly, a programmer must learn it.

The idea of tables is another characteristic specific to database programming, in addition to markup. A database can be visualized as a collection of tables. Each table represents a set of data and has a unique number of columns and rows.

Think about a library. A database that contains information about the books in the library might be made.

In this scenario, we would only require one table, which would allow us to store all the data we require.

Query Language Components

Statements in SQL begin with a word or command, such as CREATE, and terminate with a semicolon.

Additional SQL language aspects include:

Keywords: Words like ADD, JOIN, VIEW, etc. that are used to carry out different database operations. These are some SQL keywords.

Identifiers: the names of the tables, views, indexes, columns, and other database objects.

Expressions: A single symbol or a collection of symbols used to manipulate data mathematically.

To choose a subset of rows from a table, use the search conditions. Additionally enables you to build IF statements to indicate if a condition is true or not for a specific row or collection of rows.

Data kinds: When making a table, these are the different sorts of data that will be kept in each column, as the name implies. Number, string, date, and time are a few examples.

Use a Null to indicate a value that is unknowable or absent.

Comments: Describes specific SQL statement clauses.

SQL Commands List

For database operations, you need be familiar with a few commonly used SQL commands. When utilizing databases, a programmer might create the following commands:

  • TO CREATE A DATABASE, use the command
  • To make tables, type CREATE TABLE.
  • SELECT is a database search/extract method.
  • UPDATE: To modify and edit data.
  • DELETE – to remove a piece of data
  • DROP – to eliminate databases and tables
  • To add new data to a database, use the INSERT INTO command.

These are merely the most widely used commands. You as the programmer will need to utilize more commands the more intricate the database is.

When writing queries—inquiries that let you work with data in databases—these Sequel procedures are employed. In other words, a database system executes these commands after you enter them, interpreting them. A new record in the database or the establishment of a new database, for instance, could be the outcome.

Listed below are a few short SQL examples of queries:

Creates a database using CREATE DATABASE name of a database;

Name of the table: CREATE TABLE (

Data type for column 1

Data type column 2

Data type columnX);

The initial query is in charge of building a brand-new database. For instance, Facebook-like software may have databases for each of the following:

Users: This database would contain all of the user profiles’ information.

Interests: This database would contain all of the many interests that could be used to track the users’ pastimes.

Geographical locations: This database would include all of the cities where Facebook users are based.

A new table is created inside a specific database by the second query (CREATE TABLE).

What Is the Use of SQL?

In practically every area of technology where large volumes of data are involved, databases (and thus SQL) are used.

Let’s examine a few of the sectors where SQL is most frequently used.

In the financial sector, banking software and payment processors like Stripe keep and manage information about customers’ transactions and usage. Behind these procedures is a complex database that frequently makes use of SQL. Additionally, bank database systems need to adhere to the highest standards of risk compliance in the SQL code that is utilized due to additional security requirements.

Databases are used frequently by music programs like Spotify and Pandora. These apps employ Sequel databases to, among other things, store enormous collections of music files and albums by different artists, search through this data to locate what the user is looking for, and save information about users and their preferences.


Platforms for social media involve a lot of data processing. Applications like Instagram and Snapchat utilize SQL to record communications communicated between users so the user can recover the messages to read them again at a later time. These apps also use SQL to update the database when a user writes a new post or uploads a photo.

The databases all around you are being operated via the SQL language. So many pieces of software run some kind of SQL, from the social networks on your phone to the programs on your computer.

You can see why this database programming language is such a valuable tool to have in your developer’s toolbox given its broad applicability.

SQL Careers and In-Demand Skills

With 42.7% of all data job ads mentioning SQL, it is one of the most in-demand talents across all data occupations. In addition to specific positions as SQL developers, the following occupations frequently call for SQL proficiency:

DBA: Database Administrator to make it simpler to obtain data quickly and accurately, make sure that it is saved, maintained, and structured properly.

Plans develops and maintains databases for a business as a database engineer.

Massive amounts of data are sorted by data analysts in order to uncover key business insights.

To access, modify, and analyze data kept in a database, data analysts utilize SQL.

An analyst or engineer who specializes in business intelligence examines data that is used to make crucial business decisions. frequently backs statistical analytic projects.

QA Engineer/Tester: Just like penetration testers, QA engineers and testers look for, research, and report software bugs. SQL knowledge is required in order to check sure databases are operating correctly.

Software Engineer: Being familiar with SQL is quite helpful because many software engineers interact with databases either directly or indirectly.

You Should Understand SQL Database Systems

A database system is a piece of software that enables developers to employ user interfaces to interact with databases. Database systems frequently come with built-in constructors, builders, and templates.

A database programmer’s life is significantly simplified by these tools. This is so that routine chores, like clearing out the database system, can be automated using these technologies.

Let’s now examine some of the most popular SQL database architectures. Based on the popularity scores of DB-Engines, these systems are ranked. The following factors are considered when ranking

Number of online mentions of the system, as determined by the quantity of search engine results

The system’s general appeal or the volume of queries on Google Trends

The frequency of system-related technical conversations

The number of employment offers that reference the system

How many profiles on professional networks mention the system?

Appropriateness in social networks

Databases using SQL

The Oracle Database

The most popular SQL database system worldwide is Oracle. Although it is utilized throughout many different industries, data warehousing and online transaction processing are where it is most often used.


Both people and companies can use this open-source database system for nothing. Since there is no license price, small enterprises and startups love it very much. Many open-source software apps and programs use MySQL due to its open-source architecture.

Are you wondering what distinguishes SQL from MySQL? When comparing SQL and MySQL, keep in mind that while the names may be confusing to some, SQL is a language, and MySQL is a database management system. While they coexist, SQL and MySQL are very different.

You can access, modify, and edit data kept in a MySQL database using SQL.

Server Microsoft SQL

Microsoft’s proprietary SQL database management technology is called SQL Server. All current main Windows operating system versions are compatible with this database. It is utilized in both consumer software and Windows-based web servers. Its user base is big.


PostgreSQL is another free, open-source database system and a strong rival to MySQL. Due to its free license approach, technology companies frequently employ it. All popular operating systems—Mac OS, Windows, and Linux—are supported by PostgreSQL. Compared to other databases, it emphasizes using conventional SQL syntax more. The SQL standard is significantly altered by other databases (like SQL Server), making them more challenging to understand.


NoSQL, also known as “not merely SQL,” is a category of “non-relational” databases (i.e., it does not use a schema of rows and columns found in most traditional database systems).

NoSQL databases let you store data in a variety of ways based on the needs of the type of data being saved, whereas SQL databases have a fixed schema. MongoDB, Apache Cassandra, and Couchbase are some examples of NoSQL or non-relational databases. (These databases cannot be accessed with SQL.)

Given the abundance of excellent options, choosing a Sequel database system to learn can seem difficult. If unsure, choose one of the open-source, free choices like MySQL or PostgreSQL.

Locations to Learn SQL

So, how exactly does a beginner go about learning SQL? Here is a brief explanation of each step:

Know the fundamentals. Learn the fundamental SQL syntax first. The excellent SQL tutorials on W3Schools can help you become comfortable with the language.

Enroll in a SQL course. Develop your SQL knowledge by enrolling in a course.

Take on practical projects. Practice using a database and actual data.

You may find particular resources for learning SQL below, including books and training programs that will advance you from novice to expert (and ready to hunt for SQL developer jobs).

The Top SQL Learning Books

The essentials will be thoroughly covered in a well-written book on SQL, which will provide you with a solid foundation in both SQL and databases.

Additionally, you will discover how to prevent the usual errors that developers make when programming SQL.

Some well-liked books for learning SQL are listed below.

The books listed below are available on Amazon. If you click on one of the links below and make a qualified purchase, I may receive a small commission as an Amazon Associate at no additional cost to you.

Covering the features of well-known databases like Oracle, SQL Server, and PostgreSQL, the SQL Cookbook: Query Solutions and Techniques for Database Developers (through Amazon) is a useful resource.

From the very beginning, Lynn Beighley’s Head First SQL: Your Brain on SQL — A Learner’s Guide (available through Amazon) teaches you SQL.

Ben Forta’s Sams Teach Yourself SQL In 10 Minutes (available on Amazon) introduces SQL in a straightforward manner for total beginners.

A brief and clear introduction to SQL is provided in Getting Started with SQL: A Hands-On Approach for Beginners (available via Amazon).

SQL You can learn the fundamentals of database programming with the help of QuickStart Guide: The Simplified Beginner’s Guide to SQL (available through Amazon). The book progresses to more complex subjects like variations in SQL syntax between well-known database applications.

Launch School’s Introduction to SQL is a free booklet that explains how to work with and query data in contemporary relational databases.