Data Engineers
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Show more๐ 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 10 363 subscribers, ranking 19 370 in the Education category and 40 181 in the India region.
๐ Audience metrics and dynamics
Since its creation on ะฝะตะฒัะดะพะผะพ, the project has demonstrated rapid growth, gathering an audience of 10 363 subscribers.
According to the latest data from 08 June, 2026, the channel demonstrates stable activity. Although there has been a change in the number of participants by 245 over the last 30 days and by 13 over the last 24 hours, overall reach remains high.
- Verification status: Not verified
- Engagement rate (ER): The average audience engagement rate is 10.67%. Within the first 24 hours after publication, content typically collects 2.43% reactions from the total number of subscribers.
- Post reach: On average, each post receives 1 106 views. Within the first day, a publication typically gains 252 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:-.
๐ Description and content policy
The author describes the resource as a platform for expressing subjective opinions:
โFree Data Engineering Ebooks & Coursesโ
Thanks to the high frequency of updates (latest data received on 09 June, 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.
RANK() or DENSE_RANK() is a common technique for ranking and retrieving specific salary levels.
โค Explain data lineage and why itโs important in a data engineering context.
- Data lineage tracks the journey of data, essential for traceability, compliance, and debugging issues in pipelines.
โค What are window functions in SQL, and how would you use them to calculate a rolling average?
- Window functions like ROW_NUMBER(), RANK(), and LAG() are key for performing advanced analytics, such as calculating running totals or moving averages.
โค Describe the process of building a scalable data pipeline.
- Consider technologies like Apache Kafka for real-time ingestion and Spark for processing. Explain the importance of monitoring, error handling, and scalable infrastructure.
โค What strategies do you use to ensure data quality in your ETL pipelines?
- Mention data validation, deduplication, and implementing automated data checks at each stage of extraction, transformation, and loading.
โค Explain the use of CASE and COALESCE in SQL.
- These functions help with conditional logic and handling NULL values within queries, which are important for creating cleaner data outputs.
โค What are the pros and cons of using NoSQL databases vs. traditional relational databases in a data engineering project?
- Describe scenarios where NoSQL (e.g., MongoDB) might excel for unstructured data or high-velocity workloads versus relational databases for structured data with strict consistency needs.
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Hope this helps you ๐df = spark.read.csv("path/to/data.csv", header=True, inferSchema=True)
Step 2: Check for duplicates
duplicate_count = df.count() - df.dropDuplicates().count()
print(f"Number of duplicates: {duplicate_count}")
Step 3: Partition the data to optimize performance
df_repartitioned = df.repartition(100)Step 4: Remove duplicates using the
dropDuplicates() method
df_no_duplicates = df_repartitioned.dropDuplicates()Step 5: Cache the resulting DataFrame to avoid recomputing
df_no_duplicates.cache()Step 6: Save the cleaned dataset
df_no_duplicates.write.csv("path/to/cleaned/data.csv", header=True)
Interviewer: "That's correct! Can you explain why you partitioned the data in Step 3?"
Candidate: "Yes, partitioning the data helps to distribute the computation across multiple nodes, making the process more efficient and scalable."
Interviewer: "Great answer! Can you also explain why you cached the resulting DataFrame in Step 5?"
Candidate: "Caching the DataFrame avoids recomputing the entire dataset when saving the cleaned data, which can significantly improve performance."
Interviewer: "Excellent! You have demonstrated a clear understanding of optimizing duplicate removal in PySpark."
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