SQL Tutorial

SQL Tutorial

Structures Query Language is the abbreviation of SQL. To access and manipulate the databases, we use SQL. In 1986, the American National Standards Institute (ANSI) made SQL as the standard. In 1987, the International organization for standardization (ISO) made SQL as the standard. SQL can perform the following functions:

• Queries can be executed against the database in SQL.
• Data can be retrieved from the database using SQL.
• Records can be inserted into a database using SQL.
• Records can be updated into a database using SQL.
• Records can be deleted from a database using SQL.
• New databases can be created using SQL.

 The necessity to Learn SQL

The three main reasons to study SQL are:

• Everywhere we use SQL

All the biggest companies like Uber, Netflix, Airbnb, etc. in technology use SQL. Those companies that have in-built high-performance database systems like Amazon, Google, Facebook, etc. also use SQL to do analysis. SQL is found everywhere though it is old. SQL is used in everything or a derivative of SQL is used in everything.

• The demand for SQL is high

The first job in data will require SQL for entry-level jobs. In the majority of the ads for jobs, SQL is mentioned more than Python and R. Yes, learning SQL is necessary to be qualified for jobs, it sets us apart from other people who only concentrate on trending technologies.

• SQL is not a dying language

SQL is a language of choice for data engineers and data scientists. Among other popular technologies like NoSQL, Hadoop, etc. SQL is still one of the important languages not only in the field of data but also in the area of development.

Applications of SQL

 The applications of SQL are:

• Scripts for data integration

The database administrators and developers make use of SQL to write data integration scripts.

• Analytical Queries

The setting up and running of analytical queries can be done using structured query language by data analysts.

• Information Retrieval

The subsets of information from a database for analytical applications and transaction processing can be retrieved using a structured query language. Select, update, create, insert, alter, delete, add, etc. are the most commonly used structured query language elements.

• Other applications that are important

The index structures and database tables can be modified using a structured query language. By using this language, addition, updating, modification of data in the database can be done by the users.

Example:

Consider we have a table called “Customers” table consisting of information like customer ID, customer name, Contact name, address, city, postal code, and country. The below SQL query retrieves all the information from the customer table:

SELECT * FROM Customers;

 Pre-requisites to Learn SQL

There are no prerequisites as such to learn SQL, basic knowledge of relational database management system is helpful.

Target Audience

Beginners can refer to this tutorial to understand SQL basics. This tutorial is helpful for people who want to pursue a career in the field of SQL. This tutorial is good learning for all other readers.