🚀 Essential SQL Commands Every Data Professional Should Know

Whether you’re preparing for SQL interviews or working with databases daily, these commands form the backbone of SQL.

Here’s a quick refresher 👇

🔹 SELECT – Retrieve data from a table
🔹 INSERT – Add new records into a table
🔹 UPDATE – Modify existing data
🔹 DELETE – Remove specific records

📦 Database Structure

🔹 CREATE – Create new database objects (tables, databases)
🔹 ALTER – Modify the structure of an existing object
🔹 DROP – Delete an entire table or database

📊 Filtering & Analysis

🔹 WHERE – Filter records based on conditions
🔹 GROUP BY – Group rows with similar values
🔹 HAVING – Filter aggregated results

🔗 Working with Multiple Tables

🔹 JOIN – Combine data from multiple tables

⚡ Performance

🔹 INDEX – Speeds up data retrieval in large tables

📌 Tip:
Mastering these fundamentals makes solving complex SQL problems much easier.

🔥 Try this today:
Pick one command and write a small query to practice it.

#SQL #LearnSQL #DataEngineering #DataAnalytics

📊 Common SQL Window Functions You Should Know

Window functions = next-level SQL 🚀
They help you analyze data without losing rows.

🔢 ROW_NUMBER()
Gives a unique number to each row
👉 Perfect for deduplication & ordering

🏆 RANK()
Assigns rank with gaps
👉 If 2 people tie, next rank is skipped (1, 2, 2, 4)

🥇 DENSE_RANK()
Assigns rank without gaps
👉 No skipping (1, 2, 2, 3)

📈 SUM() OVER()
Calculates running totals
👉 Great for cumulative sales, revenue trends

⏮️⏭️ LAG() / LEAD()
Compare with previous/next row
👉 Useful for time-based analysis, growth tracking

⚡ Why it matters?
Because real-world data problems need row-level + aggregated insights together

🚨 New Video is LIVE! (SQL Interview Alert) 🚨

Most candidates fail these SQL questions…
Not because they’re hard —
But because they test how you think, not just syntax 👀

I’ve compiled Top 5 Hard SQL Interview Questions
that are actually asked in real interviews.

👉 Can YOU solve them all?

🎥 Watch now:
👉 TOP 5 HARD SQL INTERVIEW QUESTIONS | MOST CANDIDATES FAIL THESE QUESTIONS
https://youtu.be/mptGQeGlMWc

Comment honestly after watching:
How many did you get right? (1–5) 😏

⸻

🔥 If you’re preparing for:
• Data Analyst roles
• Data Engineering interviews
• SQL rounds

You don’t want to miss this.

#sql #dataengineer #datanalysis #sqlinterviewquestions

You can become a Data Engineer for FREE.

Here you have 5 project ideas (with resources):

𝟭. 𝗧𝗵𝗲 𝗔𝘂𝘁𝗼𝗺𝗮𝘁𝗲𝗱 𝗕𝗮𝘁𝗰𝗵 𝗣𝗶𝗽𝗲𝗹𝗶𝗻𝗲

- Get Data from an API
- Transform and load it into a database
- Schedule the process like in the real world
🔗PostgreSQL: https://lnkd.in/e2V9TR_H
🔗Openweathermap API: https://lnkd.in/eE6HgCXs

 𝟮. 𝗧𝗵𝗲 𝗠𝗼𝗱𝗲𝗿𝗻 𝗗𝗮𝘁𝗮 𝗪𝗮𝗿𝗲𝗵𝗼𝘂𝘀𝗲
- Build a local data warehouse
- Use data transformation tool to build tables
- Use a Reporting tool to build a dashboard on top

🔗dbt: https://lnkd.in/eDU_H3v8
🔗DuckDB: https://lnkd.in/exQn6wuF
🔗e-commerce dataset: https://lnkd.in/eNG55FKb

𝟯. 𝗧𝗵𝗲 𝗥𝗲𝗮𝗹-𝗧𝗶𝗺𝗲 𝗦𝘁𝗿𝗲𝗮𝗺𝗶𝗻𝗴 𝗘𝗻𝗴𝗶𝗻𝗲
- Generate real-time events
- Capture them and process them
- Store them in a local database like PostgreSQL

🔗Run Kafka on Docker: https://lnkd.in/eMKHQA9W
🔗Generate real-time data: https://lnkd.in/eEwgPEsS.

𝟰. 𝗧𝗵𝗲 𝗟𝗼𝗰𝗮𝗹 𝗗𝗮𝘁𝗮 𝗟𝗮𝗸𝗲𝗵𝗼𝘂𝘀𝗲
- Process massive datasets using distributed compute
- Store the output as optimized Parquet files in minIO.

🔗MinIO qucikstar: https://charts.min.io/
🔗 Massive Dataset: https://lnkd.in/eVGTFxNc

𝟱. 𝗧𝗵𝗲 𝗪𝗲𝗯 𝗦𝗰𝗿𝗮𝗽𝗲𝗿 & 𝗡𝗼𝗦𝗤𝗟
- Build a Web Scrapper
- Extract text, image and links from website
- Store them as documents in a document database

🔗Beautifulsoup: https://lnkd.in/eZbeAUiU
🔗MongoDB in Docker: https://lnkd.in/ez7Fzfib

---

This are REAL Data Engineering projects.

I feel confused with correlated subqueries till date 😬

Since most of folks mentioned about CTEs and Subqueries here .

I will prepare a detailed video covering only CTEs and Subqueries soon🙂

🚀 2,500 on YouTube!

From 0 to 2.5K — built purely on SQL, data engineering, and consistency.

No shortcuts. Just showing up and sharing what I know.

To everyone who subscribed, watched, liked, or shared — thank you 🙏

Next goal is 5k

👉 Better content
👉 More real-world SQL
👉 More interview-focused learning

Let’s keep building together 🚀

If you still have not subscribed,please go ahead and subscribe today
YouTube.com/@adityabansal095

I have created this video and will post it in next week

Reposting

🚨 New Video is LIVE! (SQL Interview Alert) 🚨

Most candidates fail these SQL questions…
Not because they’re hard —
But because they test how you think, not just syntax 👀

I’ve compiled Top 5 Hard SQL Interview Questions
that are actually asked in real interviews.

👉 Can YOU solve them all?

🎥 Watch now:
👉 TOP 5 HARD SQL INTERVIEW QUESTIONS | MOST CANDIDATES FAIL THESE QUESTIONS
https://youtu.be/mptGQeGlMWc

Comment honestly after watching:
How many did you get right? (1–5) 😏

⸻

🔥 If you’re preparing for:
• Data Analyst roles
• Data Engineering interviews
• SQL rounds

You don’t want to miss this.

#sql #dataengineer #datanalysis #sqlinterviewquestions

Complete Data Science Roadmap  
👇👇  

1. Introduction to Data Science  
- Overview and Importance
- Data Science Lifecycle
- Key Roles (Data Scientist, Analyst, Engineer)

2. Mathematics and Statistics  
- Probability and Distributions
- Descriptive/Inferential Statistics
- Hypothesis Testing
- Linear Algebra and Calculus Basics

3. Programming Languages  
- Python: NumPy, Pandas, Matplotlib
- R: dplyr, ggplot2
- SQL: Joins, Aggregations, CRUD

4. Data Collection & Preprocessing  
- Data Cleaning and Wrangling
- Handling Missing Data
- Feature Engineering

5. Exploratory Data Analysis (EDA)  
- Summary Statistics
- Data Visualization (Histograms, Box Plots, Correlation)

6. Machine Learning  
- Supervised (Linear/Logistic Regression, Decision Trees)
- Unsupervised (K-Means, PCA)
- Model Selection and Cross-Validation

7. Advanced Machine Learning  
- SVM, Random Forests, Boosting
- Neural Networks Basics

8. Deep Learning  
- Neural Networks Architecture
- CNNs for Image Data
- RNNs for Sequential Data

9. Natural Language Processing (NLP)  
- Text Preprocessing
- Sentiment Analysis
- Word Embeddings (Word2Vec)

10. Data Visualization & Storytelling  
- Dashboards (Tableau, Power BI)
- Telling Stories with Data

11. Model Deployment  
- Deploy with Flask or Django
- Monitoring and Retraining Models

12. Big Data & Cloud  
- Introduction to Hadoop, Spark
- Cloud Tools (AWS, Google Cloud)

13. Data Engineering Basics  
- ETL Pipelines
- Data Warehousing (Redshift, BigQuery)

14. Ethics in Data Science  
- Ethical Data Usage
- Bias in AI Models

15. Tools for Data Science  
- Jupyter, Git, Docker

16. Career Path & Certifications  
- Building a Data Science Portfolio

Like if you need similar content 😄👍

SQL & Tableau Developer / BI Analyst*

*Position:* SQL & Tableau Developer / BI Analyst

*Experience Required:* Minimum 6–8+ Years

*Duration:* 6–12 Months (Contract)

*Work Mode:* Remote (Dedicated Resource)

*Working Hours:* 3:00 PM to 12:00 AM IST (Canadian Time Alignment)

*Role Overview*

We are seeking an experienced SQL and Tableau professional who can effectively engage with clients, understand their business requirements, and deliver high-quality dashboards and analytics solutions.

*Key Responsibilities*

* Engage with clients to gather, analyze, and refine business requirements
* Design and develop interactive dashboards and reports using *Tableau*
* Write efficient and optimized *SQL queries* for data extraction and transformation
* Translate business needs into actionable data insights and visualizations
* Deliver high-quality outputs within timelines
* Maintain and enhance existing dashboards and reporting systems
* Ensure data accuracy and visualization best practices

*Required Skills & Qualifications*

* 6–8+ years of experience in SQL and BI/Analytics
* Strong expertise in *SQL* (mandatory)
* Hands-on experience with *Tableau* (mandatory)
* Proven experience in client interaction and requirement gathering
* Strong communication and stakeholder management skills
* Ability to independently drive deliverables

*Preferred Skills*

* Exposure to data warehousing concepts
* Experience working in client-facing or consulting roles

*Engagement Requirements*

* Full-time dedicated resource (no part-time engagement)
* Comfortable working in Canadian time zone (3 PM – 12 AM IST)
* Strong ownership and delivery focus

#jobalert #jobopportunity #hiring

Please ping me on linkedin urgently if you are interested in this opportunity

Linkedin.com/in/adityabansal095
Contractual job has many benefits than a permanent role

I can discuss more on this ina connect
All said this is a great opportunity