SQL Junction
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Hey guys
Freelancing job opportunity

I need a Senior Data Engineer with prior experience working with multinational clients for daily hourly support (~2 hrs/weekday, optional weekends) to work through JIRA tickets over screen share only.

Tech Stack: AWS, Python, and API work via Postman.

Schedule: Available between 3 PM – 10 PM IST (flexible around meetings).

Key Skill: Able to switch context quickly between different tasks.

Please ping me over linkedin
linkedin.com/in/adityabansal095
Reposting it ,this position is still open
The budget for this position is a decent amount

Hey guys
Freelancing job opportunity

I need a Senior Data Engineer with prior experience working with multinational clients for daily hourly support (~2 hrs/weekday, optional weekends) to work through JIRA tickets over screen share only.

Tech Stack: AWS, Python, and API work via Postman.

Schedule: Available between 3 PM – 10 PM IST (flexible around meetings).

Key Skill: Able to switch context quickly between different tasks.

Please ping me over linkedin
linkedin.com/in/adityabansal095
❤4
SQL Junction
Reposting it ,this position is still open The budget for this position is a decent amount Hey guys Freelancing job opportunity I need a Senior Data Engineer with prior experience working with multinational clients for daily hourly support (~2 hrs/weekday…
Hey Data Engineers
I’m delighted to mention that this position is towards it’s completion

We have been able to finalize one of our own member from this community for this opportunity ⚡
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I have not been feeling good , having some serious health issues

That is why I am not active on LinkedIn ,here or YouTube from the past month and continue to do so may be in next few months
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If any one needs any assistance on anything
Please ping me on linkedin
What’s the hardest part of becoming a data engineer?
Final Results
28%
Python
13%
SQL
17%
Cloud
67%
Getting Interview calls
I know getting interview calls these days has become a lot tougher

There are multiple reasons for that:
1) Beleive me when I say this many startups are heavily downsizing team size and very actively using Claude to get their work done

2) The 90 day notice period is another barrier that makes impossible to land a new job

3) Even MNCs are now expecting good AI exposure in medium paying jobs

I would suggest everyone to start looking for freelancing work ,reach out to your connections ,alumni from college ,your team members from previous companies

Do not rely solely on your current job.
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NumPy Basics! 🐍📊
Ready to make Python faster for Data Analytics & Data Engineering?

Today, we’re learning NumPy, one of the most important libraries for working with numerical data.

📚 Topics Covered:
• Arrays
•
array()

•
reshape()

•
arange()

•
zeros()
•
ones()
•
mean()
•
sum()
•
min()

•
max()


💡 Why NumPy?
Faster than Python lists ⚡
Memory efficient 🧠
Great for data processing & analysis 📈
Foundation for Data Science & ML 🚀

🔥 Mini Challenge:
Create an array from 1 to 12, reshape it into a 3×4 matrix, and find its mean, sum, minimum, and maximum.
Learn → Practice → Build → Repeat.

Stay Tuned with SQL Junction❤️👍
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❄️ Snowflake + dbt Interview Question of the Day 🔧

Q: Your dbt incremental model processes only new records based on updated_at. What happens if data arrives 2 days late? 👀

A simple filter like:

WHERE updated_at > (
SELECT MAX(updated_at) FROM {{ this }}
)

can potentially miss late-arriving records.
My approach 👇
Instead of processing only records newer than the absolute MAX timestamp,

I’d use a lookback window:

{% if is_incremental() %}

WHERE updated_at >= (
SELECT DATEADD(day, -3, MAX(updated_at))
FROM {{ this }}
)

{% endif %}

Now every incremental run reprocesses a small overlap of recent data. 🔄

But that introduces another problem:

👉 Duplicates.

So I’d pair the lookback with a reliable unique key / merge strategy and appropriate deduplication logic.

The idea is simple:

⚡ Incremental processing for performance
⏪ Lookback window for late-arriving data
🔑 Unique key / MERGE for idempotency
🧪 dbt tests for data quality

Because in production...
Incremental doesn't just mean “process less data.”
It means process less data without losing correctness. 🎯
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🚨 SQL Interview Question I Was Asked yesterday

Yesterday,I faced this SQL question in an interview, and the JOIN requirement made it more interesting than it initially looked.

You have two tables:
SalesOrder
• prodId
• orderDate
• amount
Product
• prodId
• description

The requirement:
👉 Show all products, even if they have no sales → amount should be 0

👉 Also show sales where the prodId has no matching product description → display “No Description”

🤔 The question is: Which JOIN would you use?
Don’t overthink it. Look at the two requirements carefully before voting 👇
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Which join would you use?
Final Results
11%
Inner
22%
Left
19%
Right
56%
Full Outer
7%
Cross
For those of you wondering
The correct answer is Full outer join

This question is covering both edge cases of left join and right join

So to get desired result the correct answer is full outer join

I did not expect any one to hit cross join🫠
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Top 100 Data Analyst Interview Questions

✅ Data Analytics Basics
1. What is data analytics?
2. Difference between data analytics and data science?
3. What problems does a data analyst solve?
4. What are the types of data analytics?
5. What tools do data analysts use daily?
6. What is a KPI?
7. What is a metric vs KPI?
8. What is descriptive analytics?
9. What is diagnostic analytics?
10. What does a typical day of a data analyst look like?

Data and Databases
11. What is structured data?
12. What is semi-structured data?
13. What is unstructured data?
14. What is a database?
15. Difference between OLTP and OLAP?
16. What is a primary key?
17. What is a foreign key?
18. What is a fact table?
19. What is a dimension table?
20. What is a data warehouse?

SQL for Data Analysts
21. What is SELECT used for?
22. Difference between WHERE and HAVING?
23. What is GROUP BY?
24. What are aggregate functions?
25. Difference between INNER and LEFT JOIN?
26. What are subqueries?
27. What is a CTE?
28. How do you handle duplicates in SQL?
29. How do you handle NULL values?
30. What are window functions?

Excel for Data Analysis
31. What are pivot tables?
32. Difference between VLOOKUP and XLOOKUP?
33. What is conditional formatting?
34. What are COUNTIFS and SUMIFS?
35. What is data validation?
36. How do you remove duplicates in Excel?
37. What is IF formula used for?
38. Difference between relative and absolute reference?
39. How do you clean data in Excel?
40. What are common Excel mistakes analysts make?

Data Cleaning and Preparation
41. What is data cleaning?
42. How do you handle missing data?
43. How do you treat outliers?
44. What is data normalization?
45. What is data standardization?
46. How do you check data quality?
47. What is duplicate data?
48. How do you validate source data?
49. What is data transformation?
50. Why is data preparation important?

Statistics for Data Analysts
51. Difference between mean and median?
52. What is standard deviation?
53. What is variance?
54. What is correlation?
55. Difference between correlation and causation?
56. What is an outlier?
57. What is sampling?
58. What is distribution?
59. What is skewness?
60. When do you use median over mean?

Data Visualization
61. Why is data visualization important?
62. Difference between bar and line chart?
63. When do you use a pie chart?
64. What is a dashboard?
65. What makes a good dashboard?
66. What is a KPI card?
67. Common visualization mistakes?
68. How do you choose the right chart?
69. What is drill down?
70. What is data storytelling?

Power BI or Tableau
71. What is Power BI or Tableau used for?
72. What is a data model?
73. What is a relationship?
74. What is DAX?
75. Difference between measure and calculated column?
76. What is Power Query?
77. What are filters and slicers?
78. What is row level security?
79. What is refresh schedule?
80. How do you optimize reports?

Business and Case Questions
81. How do you analyze a sales drop?
82. How do you define success metrics?
83. What business metrics have you worked on?
84. How do you prioritize insights?
85. How do you validate insights?
86. What questions do you ask stakeholders?
87. How do you handle vague requirements?
88. How do you measure business impact?
89. How do you explain numbers to managers?
90. How do you recommend actions?

Projects and Real World
91. Explain your best project.
92. What data sources did you use?
93. How did you clean the data?
94. What insight had the most impact?
95. What challenge did you face?
96. How did you solve it?
97. How did stakeholders use your dashboard?
98. What would you improve in your project?
99. How do you handle tight deadlines?
100. Why should we hire you as a data analyst?

Stay Tuned ❤️👍
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Top Data Analyst Projects That Impress Recruiters 📈💼

1. Sales Data Analysis
→ Analyze monthly/quarterly sales trends
→ Segment by product, region, and sales reps
→ Tools: Excel, SQL, Power BI/Tableau

2. Customer Retention Dashboard
→ Churn analysis and retention KPIs
→ Use cohort analysis, funnel visualization
→ Tools: Python, Tableau

3. E-commerce Data Exploration
→ Study user behavior, conversion rate
→ Analyze cart abandonment, top-selling products
→ Tools: SQL, Python (Pandas, Matplotlib)

4. HR Data Insights
→ Track hiring trends, attrition, diversity metrics
→ Build dashboards showing tenure, department stats
→ Tools: Excel, Power BI

5. Financial Data Modeling
→ Actual vs. forecasted revenue/costs
→ Include profitability ratios and variance analysis
→ Tools: Excel, Power BI, SQL

6. Web Traffic Analysis
→ Analyze Google Analytics or log data
→ Focus on user paths, bounce rates, session duration
→ Tools: Python, SQL

7. Survey Data Insights
→ Clean raw survey data, visualize trends
→ Sentiment analysis on feedback (optional NLP)
→ Tools: Excel, Python, Tableau

Tips:
• Explain the business impact of your insights
• Show your workflow: data cleaning → analysis → visualization
• Host projects on GitHub or portfolio site

Stay Tuned❤️👍

#Dataanalyst #SQL #InterviewPrep
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🔥 New YouTube Video Alert

Can You Solve This Deloitte SQL Interview Question?

You’re given a products table where the category is available only for the first product, while the following rows contain NULL.

Beverages → Coca Cola
NULL → Pepsi
NULL → Sprite
NULL → Fanta

Snacks → Lays
NULL → Doritos
NULL → Kurkure

🎯 Challenge:
How would you fill those NULL category values with the correct category?

💡 Hint: Think about Window Functions 👀

This is a great SQL problem to test your understanding of NULL handling + data transformation.

👇 What would you use?

🅰️ LAG()
🅱️ LEAD()
🅲️ LAST_VALUE()
🅳️ ROW_NUMBER()

🎬 Solution video
Fill Missing Categories in SQL | Hard Deloitte Interview Question
https://youtu.be/IX9NBK3Yx-M
🚀

Check it out now and let me know in comments ,What did you learn?

#SQL #SQLInterview #Deloitte #SQLChallenge #DataEngineering #Snowflake
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