Complete SQL Lecture Notes

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• Announcement of Delta Batch for students interested in web development.
• The course includes Front End, Back End, and Database.
• Course Duration: 4.5 months.
• Students want to create projects, participate in relevant live sessions, and seek help in resume building.
• Special 20% offer until August 21.
• New batch classes starting from August 31.

Overview of SQL Course

SQL:

• SQL (Structured Query Language) is a language used to interact with databases.
• We will not only read commands but also write and execute them.
• SQL is used by companies to access databases, such as Instagram, Uber, Amazon, Netflix, etc.

What is a database?

• A collection of data that can be easily accessed.
• Databases are generally digital.

Database Management System (DBMS):

• Software that manages databases.
• DBMS handles processes like adding, deleting, or updating data.

Types of DBMS:

1. Relational Databases (RDBMS): Data is stored in tables.
   • Example: MySQL, Microsoft SQL Server, etc.
2. Non-Relational Databases (NoSQL): Store data without tables.
   • Example: MongoDB, etc.

SQL Commands

CRUD Operations:

• Create (Creating a database/table)
• Read (Reading data from the database)
• Update (Updating data in the database)
• Delete (Deleting data from the database)

SQL Basics:

• SQL is a programming language that helps in communicating with the database.
• SQL commands are not case sensitive.

Using Tables in SQL:

• DDL (Data Definition Language): For creating, deleting, and structuring the database.
• DML (Data Manipulation Language): For adding, deleting, and updating data in the database.
• DCL (Data Control Language): For enforcing and permitting permissions on the database.

SQL Lessons:

• With the help of JOINs, we can combine data between tables.
• INNER JOIN: Shows overlapping data from both tables.
• LEFT JOIN: Shows all data from the left table and overlapping data from the right table.
• RIGHT JOIN: Shows all data from the right table and overlapping data from the left table.
• FULL OUTER JOIN: Shows all data from both tables.
• CROSS JOIN: All combinations.

Using SQL:

• Write SQL queries to derive practical results.

Views:

• Views are virtual tables used to present data in a defined format.

SQL Query Examples:

• SELECT, INSERT, UPDATE, DELETE
• Example: SELECT * FROM table_name;
• Example: INSERT INTO table_name (column1, column2) VALUES (value1, value2);

Conclusion

• Practice regularly while learning SQL.
• Understand the main concepts of SQL well.
• Practice consistently and improve continuously in SQL.

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• Students are requested to focus more on Views, Joins, and all queries.

Next Lecture:

• Topics that need more attention will be discussed further.
• Share practical experiences.
• Contact for any questions.