Advanced SQL Full Tutorial | SQL Subqueries | Structured Query Language | Windows Function | #SCALER

What is SQL?
SQL stands for Structured Query Language, and it is a standard language used to manage and manipulate relational databases. SQL allows users to create, modify, and query databases, as well as to extract and manipulate data within them.
SQL is used to perform a wide range of tasks, such as creating and modifying database schema, inserting, updating and deleting data, and querying the database to retrieve information.

What are SQL Subqueries?
Subqueries in SQL are queries that are nested within another query. They allow for more complex queries by enabling a query to reference the results of another query as a temporary table. This can be useful for filtering, sorting, and aggregating data in more complex ways than a single query can achieve.

What is Advanced SQL?
Advanced SQL refers to the use of more complex SQL features and techniques to perform advanced data manipulation and analysis. This can include subqueries, joins, aggregations, and window functions. Advanced SQL can be used to perform complex data transformations and generate insights from large and complex datasets.

What are window functions?
Window functions in SQL are used to perform calculations across a set of rows that are related to the current row. They allow for complex data analysis and aggregation without the need for subqueries or self-joins. Examples of window functions include ranking functions, aggregate functions, and analytic functions.

What is DBMS?
DBMS stands for Database Management System. It is software that allows users to create, manage, and access databases. DBMS provides a set of tools and functions for storing, organising, retrieving, and manipulating data in a structured and efficient manner. It helps to ensure data consistency, security, and integrity.

About SQL interviews-
These are job interviews where the candidate is evaluated on their knowledge of SQL, including their ability to write and optimise SQL queries, create and manipulate databases, and understand database design principles. These interviews are common in data-related roles such as data analyst, data engineer, and database administrator.

Topics covered:
0:00 - Introduction
0:34 - Window Functions in SQL
12:26 - Window Functions demo on a sample database
17:26 - Rank Function in SQL
27:43 - Rank Functions with Window demo
31:16 - SQL Subqueries
36:26 - When to use: Subqueries vs Join two tables
42:16 - 4 Rules to follow while writing a Subquery
42:24 - Rule 1
43:00 - Rule 2
44:05 - Rule 3
46:05 - Rule 4
46:50 - Difference B/W Correlated & Non-correlated Subquery

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[osoriomatucurane]

Awesome, crtystal clear and concise. The best Window functions tutorial I have ever found.

[optiongreeks_]

Genuinely you taught the concepts in such a ways that the 1st year under graduate student can also understand very

[wckd]

It's literally the best video for understanding window functions and sub queries

[harshadak]

Thanks for this video. Its really helpful ...!!!

[osoriomatucurane]

Sir, sorry I am not clear when to choose between running a query with join and using subquery when the result set comes from two tables, like retrieving employment details (empid, name, dept, salary) given the condition or criteria selection is department_name = XXXX?

[niyatishah]

Is it possible to access the "HR" database?

[wonderfulvamsi]

Why do we need Window functions?
When I can simply left join the original table and the aggregated table (using group by) to achieve the same result?