
Download the PostgreSQL installer and install the PostgreSQL database software. Save your password, choose installation options, and connect to the database to verify setup before practice.
Create customers and orders tables from the pdf 'tables creation command' with pgAdmin, then import 2,000 utf-8 csv records to validate data for real-world sql interview questions.
Practice sql queries with the customers and orders tables, filtering by year 2024 using where and extract functions, select all fields with * and respect primary keys.
Count customers by country using the customers table and group by country, counting with customerId to show origin country distributions across 2023–2024.
Convert sign-up dates to year-month, group by year and month, and count sign-ups in the customers table to identify October 2024 as the peak.
Identify customers who bought exactly eight items in 2023 by summing items per customer from the orders table, using extract, group by, and having to filter aggregates.
Calculate the number of distinct customers who bought in 2024 but not in 2023, using where, distinct, and a not in subquery on customer IDs.
Calculate each customer's lifetime total spend from the orders, using sum and group by, then sort by total spend descending to identify the second highest.
Extract the year from the orders date, sum the price to compute revenue, and group by year and acquisition channel to show income by channel for each year.
Compute total revenue by customer platform by joining the customers and orders tables, using on to connect the tables and group by to aggregate revenue for Android, iOS, and Web.
Learn to compute countrywise revenue for 2023 by joining customers and orders, aggregating total amount per country, and identifying the top country using order by and limit.
Join the customers, orders, and order_products tables to calculate the total quantity sold in 2023 for USA customers, yielding 866 units.
Rank orders by total amount using a window function and partition by device platform to compare Android, Web, and iOS revenue.
Learn to solve question 5 by joining customers and orders, rank orders by amount in each country using a window function, and use a subquery to fetch the top order.
Do you know the basics of SQL but you feel feel that you lack practical experience? You are not alone. Many beginners understand what SELECT and GROUP BY do, but they struggle to combine them to answer real business questions during technical interviews.
Welcome,
At this course we bridge the gap between theory and practice. We don't just talk about code; we act as Data Analysts for a fictional e-commerce company. We will use PostgreSQL to analyze real-world data, calculate revenue, track the best customers , and find helpful insights in the data.
What will you practice in this course? Based on real interview questions, we will cover:
Business Aggregations: Use COUNT, SUM, and AVG to calculate total orders and revenue per channel.
Advanced Logic: Understand exactly when to use HAVING vs. WHERE to filter complex results.
Customer Analysis: Solve complex scenarios like "Who bought this year but not last year?"
Date Trends: Analyze sales performance by year and month using Date functions.
Window functions
With, Case, Sub queries and all the most advanced and complex SQL methods.
How is the course structured?
We believe in learning by doing. The course is divided into three main parts:
Guided Exercises
Self-Practice
Detailed Solutions
Who is this course for?
Aspiring Data Analysts preparing for technical interviews.
Students and Juniors who want to build a portfolio.
Anyone who wants to move from "learning SQL" to "using SQL."
Enroll today and start building your practical data skills!