Data Engineers
Free Data Engineering Ebooks & Courses
Show more📈 Analytical overview of Telegram channel Data Engineers
Channel Data Engineers (@sql_engineer) in the English language segment is an active participant. Currently, the community unites 10 888 subscribers, ranking 18 004 in the Education category and 35 805 in the India region.
📊 Audience metrics and dynamics
Since its creation on невідомо, the project has demonstrated rapid growth, gathering an audience of 10 888 subscribers.
According to the latest data from 26 August, 2026, the channel demonstrates stable activity. Although there has been a change in the number of participants by 277 over the last 30 days and by 8 over the last 24 hours, overall reach remains high.
- Verification status: Not verified
- Engagement rate (ER): The average audience engagement rate is 11.06%. Within the first 24 hours after publication, content typically collects 2.83% reactions from the total number of subscribers.
- Post reach: On average, each post receives 1 204 views. Within the first day, a publication typically gains 308 views.
- Reactions and interaction: The audience actively supports content: the average number of reactions per post is 5.
- Thematic interests: Content is focused on key topics such as sql, learning, analytic, engineer, link:-.
📝 Description and content policy
The author describes the resource as a platform for expressing subjective opinions:
“Free Data Engineering Ebooks & Courses”
Thanks to the high frequency of updates (latest data received on 27 August, 2026), the channel maintains relevance and a high level of publication reach. Analytics show that the audience actively interacts with content, making it an important point of influence in the Education category.
MongoDB is a flexible, document-orientated, NoSQL database program that can scale to any enterprise volume without compromising search performance.This Post includes a MongoDB cheat sheet to make it easy for our followers to work with MongoDB. Working with databases Working with rows Working with Documents Querying data from documents Modifying data in documents Searching
netflix_data with the following columns:
- user_id: Unique identifier for each user
- subscription_plan: Type of subscription (e.g., Basic, Standard, Premium)
- genre: Genre of the content the user watched (e.g., Drama, Comedy, Action)
- timestamp: Date and time when the user watched a show
- watch_duration: Length of time (in minutes) a user spent watching
- country: User’s country
The main objective is to figure out how to get insights into user behavior, such as which genres are most popular or how watch duration varies across subscription plans.
---
### Typical Interview Question
> “Using the netflix_data table, find the top 3 genres by average watch duration in each subscription plan, and return both the genre and the average watch duration.”
This question tests your ability to:
1. Filter or group data by subscription plan.
2. Calculate average watch duration within each group.
3. Sort results to find the “top 3” within each group.
4. Handle tie situations or edge cases (e.g., if there are fewer than 3 genres).
---
### Step-by-Step Approach
1. Group and Aggregate
Use the GROUP BY clause to group by subscription_plan and genre. Then, use an aggregate function like AVG(watch_duration) to get the average watch time for each combination.
2. Rank Genres
You can utilize a window function—commonly ROW_NUMBER() or RANK()—to assign a ranking to each genre within its subscription plan, based on the average watch duration. For example:
AVG(watch_duration) OVER (PARTITION BY subscription_plan ORDER BY AVG(watch_duration) DESC)
(Note that in many SQL dialects, you’ll need a subquery because you can’t directly apply an aggregate in the ORDER BY of a window function.)
3. Select Top 3
After ranking rows in each partition (i.e., subscription plan), pick only the top 3 by watch duration. This could look like:
SELECT subscription_plan,
genre,
avg_watch_duration
FROM (
SELECT subscription_plan,
genre,
AVG(watch_duration) AS avg_watch_duration,
ROW_NUMBER() OVER (
PARTITION BY subscription_plan
ORDER BY AVG(watch_duration) DESC
) AS rn
FROM netflix_data
GROUP BY subscription_plan, genre
) ranked
WHERE rn <= 3;
4. Validate Results
- Make sure each subscription plan returns up to 3 genres.
- Check for potential ties. Depending on the question, you might use RANK() or DENSE_RANK() to handle ties differently.
- Confirm the data type and units for watch_duration (minutes, seconds, etc.).
---
### Key Takeaways
- Window Functions: Essential for ranking or partitioning data.
- Aggregations & Grouping: A foundational concept for Analytics Engineers.
- Data Validation: Always confirm you’re interpreting columns (like watch_duration) correctly.
By mastering these techniques, you’ll be better prepared for SQL interview questions that delve into real-world scenarios—especially at a data-driven company like Netflix.