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SQL Server Tutorial for Beginners

A SQL Tutorial guide can help you in learning SQL basics which would in turn help you in becoming an expert SQL developer. You will get a detailed idea of what is Structured Query Language and how to deploy SQL to work with the relational database management system. Basically, Structured Query Language is used to work with a relational database and store, retrieve, and manipulate data stored in relational databases.

SQL Tutorial for Beginners

In this blog for “SQL Tutorial Guide for Beginners,” you will learn SQL commands, syntax, data types, working with tables & queries, etc. To know more in detail what exactly SQL contains, you should download the syllabus first.

This blog is suitable for college students who want to learn SQL from basics. It is beneficial for software developers, architects, database administrators, and managers who want to take the first step to learn SQL to excel in their careers. There are no prerequisites to learn SQL, but a basic understanding of database or computer languages can be beneficial. You can join an online SQL training program from JanBask Training for ultimate growth and achievement.

What is DBMS?

A DBMS or Database Management System is a software system that is used to store or manage the data. A DBMS guarantees durability, confidentiality, and quality of the data. The most popular category of DBMS is RDBMS (Relational Database Management System) where a database consists of a structured set of tables, and each row in the table is defined as the record.

What is SQL?

SQL or Structured Query Language is a standard language for manipulating data in a DBMS. Simply, it is used for handling data in a DBMS. Here are the different types of SQL statements:

What is SQL?

  • DDL or Data Definition Language is used to create objects like tables or schemas in a database.
  • DML or Data Manipulation Language is used to search, insert, update, and delete data in a database.
  • DCL or Data Control Language is used to manage or manipulate access rights on database objects.

To know more on SQL, click here.

What is a Query?

An SQL Query is a set of instructions given to the database system. It is telling a database what information you would like to get from the database. For example, to fetch the name of students from a database table “STUDENT,” you should use the following query:

Select student_name from STUDENT;

Different types of Queries in SQL

  1. Select Query
  2. Action Query
  3. Parameter Query
  4. Action Query

What is SQL Process?

When you want to execute SQL commands for any DBMS system, you should use the best method to carry out your request, and SQL engine can check how to interpret those tasks nicely. Here are the major components available in a SQL Process.

SQL query engine, SQL optimization engine, SQL Query Dispatcher, and a Classic Query Engine. With a Classic Query Engine, you can manage all the non-SQL queries. Here is the pictorial representation of a SQL Process for your reference:

What is SQL Process?

SQL Optimization

Working with queries is not really tough, but you should understand how data storage works and how queries are read to optimize the SQL Performance. Optimization in SQL is based on two factors. These are, you should make the right choices when defining the database structure and use the most appropriate methods to read the data.

Why is SQL so Popular?

SQL is used extensively because of the following reasons:

  • SQL allows you to access the data within relational databases.
  • It helps you in describing the data within databases using SQL.
  • It helps you in manipulating data within relational database systems.
  • It can be embedded with other languages with SQL modules or libraries.
  • It helps you in setting permissions on tables, procedures, or views, etc.

What are SQL Features?

Here are some of the best features of SQL that makes it ubiquitous for developers:

  • It is simple and easy to learn.
  • It can work with different databases like Oracle, MySQL, IBM, Microsoft, etc.
  • It is based on ANSI standards for database creation and manipulation.
  • It has a well-defined structure with well-defined standards.
  • It helps in retrieving a large amount of data effectively.
  • It helps in managing databases without any knowledge of coding.

What are SQL applications?

SQL applications will help you to understand how much a SQL database is important in this data-driven world where maintaining huge databases are the norm of the day.

Read: Coalesce Function SQL Server Example
  • It can be used to create a database independently, define its structure, using it, then discard it when you are done.
  • It can be used to manipulate an already existing database. It is a powerful language to enter, modify, and extracting data about a database.
  • It can be used to secure your database against threats or corrupts.
  • It is extensively used as a client-server language for connecting front-ends with back-ends and supporting the client/server architecture too.
  • It can be used in the 3-tier architecture of a client, an application server or a database for defining the internet architecture.

Why should you learn SQL?

One thing that is common to RDBMS given by big corporation is Structured Query Language. So, if you are planning to learn, then it can be a bright career choice with a lot of roles and responsibilities.

SQL Server quiz

Moreover, it is important for a data scientist with a background in data science. They also have to deal with relational databases and making queries using Structured Query Language. Take a quick quiz to check your level of skills before you continue further.

SQL Tutorial Guide for Beginners

What is a Table in SQL?

Tables are used to store data and information in SQL Server. Every table in SQL is stored with a unique name and composed of rows and columns. Moving ahead, you need to define a data type to store information in a table.  If you want to use tables for your database application, you should know how to create it and add data to the table. The CREATE TABLE keyword is used to create a table in the SQL. Its basic syntax can be given as below.


CREATE TABLE new_table_name
(
First_column first_column_data_type,
Second_column second_column_data_type,
Third_column third_column_data_type,
---
Last_column last_column_data_type
);

Here, you have to focus on three major categories, when creating a table for the first time.

  • You should not be able to enter Not Null values in the table.
  • You cannot use duplicate values, so put a UNIQUE keyword in between.
  • Define a primary key for the column that is Unique and Not Null. We will be discussing the primary key in SQL in detail later.

To get a depth idea of Tables in SQL, Click Here.

What is a primary key in SQL?

A primary key is a special column within a SQL table that is used to identify records uniquely. Every time you are creating a table in SQL, you should add a primary key first. Also, don’t forget to add primary key constraints to make the concept little more meaningful. When multiple primary keys are defined for a table, it is named as the composite primary key.

The objective of using a primary key is enhancing performance and storage. If you are using multiple columns as the primary key, then you require more storage in that case. When we are talking about the performance, primary key addition generally results in enhanced performance standards.

A Primary key is a critical component in SQL database system, and you can use the foreign key in the absence of a primary key. Every SQL developer has to deal with a primary key during their work experiences. The real-life examples of primary key are Roll numbers in schools or college, Aadhar card number, employee ID, etc. Adding a primary key is easy in SQL server. Here is the syntax for your reference.


CREATE TABLE 
Column1 data_type[(size)] NOT NULL PRIMARY KEY,
COLUMN2 data_type [(size)],
….);

To know more on the primary key, its features, and technical advantages, Click Here.

SQL Data Types

When you create a table in SQL, you want to store data as well. For this purpose, you need Data types. It has to be defined for each entry in the SQL table. For example, if you want to store the numeric data, then “int” data type can be used. If you want to store the character data, then “char” data type can be used. In this way, there are plenty of data types available in the SQL as per the requirement.  They are divided into five major categories as given below.

  1. Exact Numeric Data Types
  2. Approximate Numeric data types
  3. Character String data types
  4. Date and Time Data types
  5. Binary Data Types
  6. Unicode Character String data types
  7. Miscellaneous Data types

All these data types have different range and rules for using them. To get a detailed idea of Data types in SQL, click here.

Different Types of Joins in SQL

A SQL Join is used to merge data from different sources or tables. SQL database is used to manage data or information in the form of tables. It is necessary to define a clear relationship among different tables and datasets to perform an action. These relations are defined with the help of joins in SQL. They are divided into two major categories: Inner Joins and Outer Joins.

joins

An inner join in SQL is used to return results from two different tables. Rows are combined generally based on the requirements. Here is the Venn Diagram representation of the Inner Join in SQL:

inner join

Read: What is a CASE Statement in the SQL?

An Outer Join returns the rows that are not common in both the table and inner join returns the common rows in both the tables. So, the output will be different here when compared to the result of the inner join. An outer join is further divided into three broad categories:

  • Left Outer Join
  • Right outer Join
  • Full Outer Join

Null values are also taken as the part of inner and outer joins as no value present sometimes in columns. In the case of a left outer join, all the data in the left side is returned as the outcome. Similar, in the case of the right outer join, all the data on the right side is returned as the outcome. Full outer join is used to combine the whole data from two tables, either it is common or not. To know about SQL Joins in detail with examples, Click Here.

What is a Foreign key in SQL?

A foreign key is used to establish a relationship among different tables, and it explains to you how is data related among multiple tables. The major benefits of using a foreign key in SQL is Data Integrity, and it avoids notifications that could violate the data integrity rules.

A Foreign key is as important as a primary key, and it holds the capability to manage data updates in interesting ways. It is used to refer the primary key of another table and helps in maintaining links among tables. In the case of a complex database system, it is necessary maintaining a healthy relationship among tables logically, and it can be done gracefully with the help of foreign keys. To go a little deeper into the concept, Click Here.

Keep in mind that using foreign key is not as easier as primary keys. You have to put extra efforts to know how can you use the Foreign key for your database tables. The best idea is to learn the implementation of different keys in SQL practically. For this purpose, take SQL certification course from JanBask Training now and start learning practical aspects of SQL right away. Before you enroll for the final program, take a demo class first to get an idea of the online learning environment at JanBask Training.

What is a Candidate Key in SQL?

Keys can be defined as a set of attributes that are generally required for accessing tuples from a database table. They are used to construct relationships among two tables and work similarly to a primary key. The major difference is that the primary key can be single, and candidate keys are generally multiple.

In usual practice, keys are needed to improve the overall performance of a database, so they should be selected wisely. A wrong selection of keys may put an adverse impact on database performance. A candidate key can qualify as a primary too, but it should be Unique and Not Null for this purpose.

When you start working with databases, you will realize that primary keys change seldom. When all candidate keys qualify to become a candidate key, here an experienced DBA should decide which can be used as the primary key in that case. It is not possible establishing a relationship without a candidate key.

To know more on a candidate key in SQL and how is it different from the primary key, Click Here.

What is a Composite Key in SQL?

Keys are the vital components to set up a connection among different database tables. There are a few imperative keys in SQL like primary key, candidate key, foreign key, or composite key, etc. We have already discussed the primary key, candidate key, foreign key in the earlier section. Here, we will be discussing a composite key in SQL and why is it significant for database applications.

A composite key is used to combine at least two columns in the table that are utilized to remarkable recognize each row in a table. It makes sure that column data is unique before they are consolidated. In a few cases, the composite key can qualify as a primary key too based on the arrangement of sections.

To know more on a composite key in SQL and how is it different from the primary key and the Foreign key, Click Here.

SQL Command Cheat Sheet

An SQL commands cheat sheet gives you a complete idea of popular SQL commands that can be used with your database to improve its performance incredibly. When all commands are available in a single place, they can be used quickly without wasting time. They can be divided into different categories further as DDL commands, DCL commands, DML commands, etc. Once you go through the SQL command cheat sheet, it can be used to perform different operations in different situations.

Tips for using SQL command Cheat Sheet

  • It can be used with an IDE or tool where users are trying to connect with the database.
  • It can be used to connect with different databases and manages complex data operations.
  • It uses a set of the aggregate function to use along with SQL cheat sheet and performing complex data operations based on the data query.
  • It helps you in managing View, Triggers, and Indexes, etc.
  • It includes a set of logical and comparison operator to execute a query.
  • It includes a complete set of data types (more than 40 in SQL) that are used to store data in a database using different formats like numeric, characters, strings, floats, etc.

To know the list of commands in a SQL cheat sheet, Click Here.

Complex Queries in SQL

We have already discussed what a query in SQL is. This is the time to discuss the complex SQL queries and when they are used. A query becomes complex when it is using multiple joins, multiple nested conditions, multiple comparison or logical operators, multiple operators to act. It is generally difficult to understand how should we use different SQL concepts together.

Read: How to Create Stored Procedure & Trigger in SQL Server

For writing a complex SQL query in SQL, you should consider the following facts:

  • Focus on database relationships; how are tables connected together.
  • Focus on the outcome, what you need to compute finally.
  • You should know how to break queries into manageable parts.
  • You should know how to aggregate the result sets.
  • Write a query that is easy to read and understand.
  • You should know how to debug a query.

For debugging a complex SQL query in SQL, you should consider the following facts:

  • Check the syntax and logic
  • Check the SQL joins
  • Check attributes
  • Check predicates
  • Check nested queries, and more.

It is good writing simple queries in SQL instead of complex SQL queries; otherwise, it may confuse readers and developer both. Here, we have given a brief idea of complex SQL queries. To know these queries in detail and why should you avoid them, Click Here.

What is a subquery in SQL?

A subquery is a nested or inner query in SQL within another SQL query, and it is embedded with the where clause to process the final outcome. SQL subqueries are generally used with comparison operators and SELECT, DELETE, INSERT, and UPDATE statements. A subquery is usually composed of a single column and enclosed within parenthesis. It can be used with Group By clause, but it should not be used with Order By clause. It can be used to return multiple rows together with the “IN” operator. It cannot be enclosed quickly within a set function. The basic syntax of a SQL subquery is given below.


SELECT column_name [, column_name ]
FROM table1[, table2 ]
WHERE column_name OPERATOR
(SELECT column_name [, column_name ]
FROM table1 [, table2 ]
[WHERE])

It is possible joining subqueries in SQL if required. When subqueries are joined together, the final outcome is not so stringent, so it is better using Where clause in that case. You must be wondering where should you use a subquery. It can be used to enhance the overall performance of queries when used appropriately.

To understand the concept of SQL subqueries in depth, Click Here.

What is a LIKE operator in SQL?

It is a logical operator to check if a specified string matches the desired pattern or not. A pattern is made up of regular expressions or wild characters, etc. It can be used with different SQL statements like DELETE, WHERE, SELECT, UPDATE, etc. It is used to filter rows based on matching patterns. Here is the basic syntax of a LIKE operator in SQL for your reference:

Colum | expression LIKE pattern [ESCAPE escape_character]

Let us understand the concept with a real-life example. Consider you are availed with a specific portion of the address then how to fetch the complete one. You can use LIKE operator in this situation to filter addresses and fetch the desired output. It is clear from the discussion that the SQL LIKE operator is a wonderful searching technique when we are not sure what we are looking exactly. TO learn LIKE operator in SQL with examples, Click HERE.

SQL Formatter

Would you like to read a length plain code? No one would like actually. When writing a detailed SQL script, there is a lot of unformatted SQL code that is tough to understand. Here you should use a SQL formatter with fabulous formatting options to make things easier for you. A formatted SQL script is easy to read consistently.

free SQL Server demo

If you are performing formatting manually, then it can be a time-consuming process. The best idea is using formatting tools to accelerate the process and make it more efficient for developers as well. One of the popular options in SQL formatting includes Indenting. It is used to align the content at the right space in a consistent manner. If you want to how can you use a SQL formatter to manage the highly complex code, then Click Here.

Top 100 SQL Interview Questions & Answers

The increased demand for SQL has raised the demand for skilled database developers too. There is a need for individuals who can control database systems effectively. For this purpose, you should be prepared well before you go for an SQL interview. We have compiled a list of top 100 SQL interview questions with researched answers that are frequently asked by developers. The discussion will start from the basics then you can see some advanced level questions too that are suitable for intermediates having 2-5 years of experience or even more. To go through the complete list of “Top 100 SQL interview question”,  Click Here. Happy Reading!

Final Words:

This SQL tutorial guide for beginners is suitable for students who want to learn SQL online. Here, we have discussed the top concepts that are frequently used by expert database developers. The discussion doesn’t end here; you can expand your knowledge base further by joining the SQL certification program at JanBask Training.

You will also get familiar with using SQL at the workplace. We wish you a successful career in the database domain with an attractive salary package. To know more on our SQL course, contact our experts now!

Read: RDBMS Interview Questions

SQL Tutorial Overview

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    JanBask Training is a leading Global Online Training Provider through Live Sessions. The Live classes provide a blended approach of hands on experience along with theoretical knowledge which is driven by certified professionals.


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