SQL Tutorial

What will you learn in this SQL Tutorial?

This SQL Tutorial for Beginners is a complete package for how to master SQL online. In this tutorial, you will get a clear idea of SQL Basics, what Structured Query Language is, and how you deploy SQL to work with a relational database system.

So, a structured query language is a language that is used to operate relational databases. Some of the major ways in which SQL is used in conjunction with a relational database are for the purposes of storing, retrieving, and manipulating data stored in a relational database.

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What is SQL?

Structured Query Language, or SQL, is the language that helps manage databases. It helps in creating data, operating on it, and retrieving it. It is also the standard language used in the Relational Database Systems. Various Relational Database Systems like MySQL, Sybase, Oracle, MS Access, Postgres, Informix, SQL Server, etc., have SQL as their base language.

To learn about what is SQL, first, let us compare SQL with NoSQL in the below table:

The language to communicate with the relational database is SQL or Structured Query Language. SQL programming helps to operate the relational database and derive information from it.

Some of the operations that SQL does include, are the creation of a database, fetching, modifying, updating, and deleting the rows along with storing, manipulating, and retrieving data within the relational database. SQL programming is an ANSI standard language but there are a lot of versions of SQL in use as well.

Why SQL is required?

SQL is required because it offers the following advantages for the users:

• SQL helps in creating new databases, views, and tables.
• It is used for inserting, updating, deleting, and retrieving data records in the database.
• It enables users to interact with data stored in relational database management systems.
• SQL is required to create views, stored procedures, and functions in a database.

Why is SQL programming so widely used?

Structured Query Language programming is used so extensively for the following reasons.

• SQL lets you access any data within the relational database
• You can describe the data in the database using SQL
• Using SQL you can manipulate the data with the relational database
• SQL can be embedded within other languages through SQL modules & libraries
• SQL lets you easily create and drop databases and tables
• SQL allows you to create views, functions, and stored procedures in databases
• Using SQL you can set permissions on procedures, tables, and views.

Features of SQL

Here in this section of the MS SQL tutorial for beginners, we list some of the top features of SQL that make it so ubiquitous when it comes to managing relational databases.

• SQL is a very simple and easy-to-learn language.
• SQL is versatile as it works with database systems from Oracle, IBM, Microsoft, etc.
• SQL is an ANSI and ISO standard language for database creation and manipulation.
• SQL has a well-defined structure as it uses long-established standards
• SQL is very fast in retrieving large amounts of data very efficiently.
• SQL lets you manage databases without knowing a lot of coding.

Applications of SQL

Here in this section of the Advanced SQL tutorial, we will learn about SQL applications that make it so important in a data-driven world where managing huge databases is the norm of the day.

• SQL is used as a Data Definition Language (DDL) meaning you can independently create a database, define its structure, use it and then discard it when you are done with it
• It is also used as a Data Manipulation Language (DML) which means you can use it for maintaining an already existing database. SQL is a powerful language for entering data, modifying data, and extracting data with regard to a database
• It is also deployed as a Data Control Language (DCL) which specifies how you can protect your database against corruption and misuse.
• It is extensively used as a Client/Server language to connect the front end with the back end thus supporting the client/server architecture
• It can also be used in the three-tier architecture of a client, an application server, and a database that defines the Internet architecture.

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SQL Process

When you run an SQL command against any RDBMS, the system figures out the best way to carry out your request, and the SQL engine figures out how to interpret it.

This procedure has a number of different components. Query Dispatcher, Optimization Engines, Classic Query Engine, and SQL Query Engine are some of these elements. Non-SQL queries are handled by the classic query engine, but logical files are not handled by the SQL query engine.

SQL Syntax

The syntax is a collection of rules and guidelines that SQL adheres to. Since SQL is case insensitive, the terms SELECT and select in SQL statements have the same sense. MySQL, on the other hand, distinguishes between table names. If you’re using MySQL, you’ll need to specify table names exactly as they appear in the database.

Various SQL keywords are:

• INSERT
• UPDATE
• DELETE
• ALTER
• DROP
• CREATE
• USE, etc.

What You Can Do with SQL?

With SQL, we can create, update, reorganize and modify data. We can solve spreadsheets problems, such as in Microsoft Excel we can compile a lot of data because SQL is designed to compile and handle data in much larger quantities. With an SQL Server, we can transform raw data into meaningful insights and business intelligence operations can also be performed. Data integrations and ETL operations are easy with SQL.

SQL Data Filtering

SQL has the ability to filter the data in a database that is we can select only required records from a set of data. The filter is a SQL WHERE clause that specifies a set of comparisons that must be true in order for a data item to be returned for SQL database and internal data types. Typically, these distinctions are made between field names and their values.

Why should you learn SQL online?

Today, regardless of the relational database systems by major corporations like Oracle, IBM, Microsoft, and others, the one thing that is common to them is the Structured Query Language or SQL.

So if you master  SQL online then you will be able to pursue a very broad career spanning a lot of roles of responsibilities. Also if you are learning SQL then it is important for a data science career as well since a data scientist will also have to deal with relational databases and query them using the standard language SQL.

Aggregate Functions

An aggregate function in database management is a function that groups the values of multiple rows as input on certain parameters to create a single value with more significant significance.

Various Aggregate Functions

COUNT– the number of elements in the given group is counted

SUM– computes the total of the given attribute/expression in the specified category

AVG– computes the average value of a given attribute/expression in a fixed category

MIN– finds the smallest value in a set of numbers

MAX– returns the highest value in the defined group

Recommended Audience

This SQL tutorial can be beneficial to anybody who wants to learn SQL online. Software developers, database administrators, architects, and managers can take this Free SQL tutorial as a first step toward learning SQL and Excel in their careers.

Prerequisites for SQL Tutorials

There are no prerequisites for learning SQL from this SQL tutorial for beginners. If you have a basic understanding of computer languages and databases, then it is beneficial.