๐ถ ASO Corgi โ platform for the App Store developers.
Find the keywords your apps and competitors rank for, and track positions across every country in one place.
๐ Keyword research: by topic, by your app's languages, from App Store suggestions, by competitors, and with AI analysis.
โข Rankings by country โ history, charts, demand score (0โ100)
โข Global search across any App Store storefront
โข ASO assistant builds your listing for each locale
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๐ 14 days of Pro, free ๐ (no card required)
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Find the keywords your apps and competitors rank for, and track positions across every country in one place.
๐ Keyword research: by topic, by your app's languages, from App Store suggestions, by competitors, and with AI analysis.
โข Rankings by country โ history, charts, demand score (0โ100)
โข Global search across any App Store storefront
โข ASO assistant builds your listing for each locale
โข App Store top charts for any country
๐ 14 days of Pro, free ๐ (no card required)
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โค5
๐๐ผ๐ผ๐๐ ๐ฌ๐ผ๐๐ฟ ๐๐ฎ๐ฟ๐ฒ๐ฒ๐ฟ ๐๐ข๐ญ๐ก ๐๐ฅ๐๐ ๐๐ถ๐๐ฐ๐ผ ๐๐ผ๐๐ฟ๐๐ฒ๐ + ๐ฆ๐ต๐ผ๐๐ฐ๐ฎ๐๐ฒ ๐๐ถ๐ด๐ถ๐๐ฎ๐น ๐๐ฎ๐ฑ๐ด๐ฒ๐
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โ 100% FREE Learning
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๐ Start Learning Today. Earn Official Cisco Badges. Get Career Ready!
๐ซStand out in the job market with globally recognized tech skills
โ 100% FREE Learning
โ Official Cisco Digital Badges
โ Self-Paced Online Courses
โ Beginner-Friendly Content
โ Hands-on Labs (Selected Courses)
โ Globally Recognized Skills
๐ ๐๐ป๐ฟ๐ผ๐น๐น ๐๐ผ๐ฟ ๐๐ฅ๐๐๐:
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๐ Start Learning Today. Earn Official Cisco Badges. Get Career Ready!
โค4
๐๐ป๐๐ฒ๐ฟ๐๐ถ๐ฒ๐๐ฒ๐ฟ:
You have 2 minutes to solve this SQL query.
Find the departments where the average salary is greater than the company's overall average salary.
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
department,
AVG(salary) AS average_salary
FROM employees
GROUP BY department
HAVING AVG(salary) > (
SELECT AVG(salary)
FROM employees
);
๐ก Explanation:
The query compares each department's average salary with the company's overall average salary.
โข GROUP BY department calculates the average salary for each department.
โข The subquery computes the overall average salary across all employees.
โข HAVING filters only those departments whose average salary exceeds the company average.
This question tests your understanding of:
โ GROUP BY
โ HAVING
โ Aggregate Functions AVG
โ Subqueries
๐ฏ Expected Output Example
Department: Average Salary
IT: 88,500
Finance: 84,000
HR is excluded because its average salary is below the company average.
๐ Alternative Using a Common Table Expression CTE
WITH company_avg AS (
SELECT AVG(salary) AS avg_salary
FROM employees
)
SELECT
department,
AVG(salary) AS average_salary
FROM employees, company_avg
GROUP BY department, company_avg.avg_salary
HAVING AVG(salary) > company_avg.avg_salary;
Using a CTE can improve readability, especially when the same calculated value is reused in larger queries.
๐ Tip for SQL Job Seekers:
Interviewers often ask questions that compare group-level aggregates with overall aggregates. Master the use of HAVING with subqueriesโitโs a key SQL pattern.
โค๏ธ React with โค๏ธ for more SQL interview challenges!
You have 2 minutes to solve this SQL query.
Find the departments where the average salary is greater than the company's overall average salary.
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
department,
AVG(salary) AS average_salary
FROM employees
GROUP BY department
HAVING AVG(salary) > (
SELECT AVG(salary)
FROM employees
);
๐ก Explanation:
The query compares each department's average salary with the company's overall average salary.
โข GROUP BY department calculates the average salary for each department.
โข The subquery computes the overall average salary across all employees.
โข HAVING filters only those departments whose average salary exceeds the company average.
This question tests your understanding of:
โ GROUP BY
โ HAVING
โ Aggregate Functions AVG
โ Subqueries
๐ฏ Expected Output Example
Department: Average Salary
IT: 88,500
Finance: 84,000
HR is excluded because its average salary is below the company average.
๐ Alternative Using a Common Table Expression CTE
WITH company_avg AS (
SELECT AVG(salary) AS avg_salary
FROM employees
)
SELECT
department,
AVG(salary) AS average_salary
FROM employees, company_avg
GROUP BY department, company_avg.avg_salary
HAVING AVG(salary) > company_avg.avg_salary;
Using a CTE can improve readability, especially when the same calculated value is reused in larger queries.
๐ Tip for SQL Job Seekers:
Interviewers often ask questions that compare group-level aggregates with overall aggregates. Master the use of HAVING with subqueriesโitโs a key SQL pattern.
โค๏ธ React with โค๏ธ for more SQL interview challenges!
โค12
๐ ๐๐ผ๐ผ๐ด๐น๐ฒ ๐๐ฅ๐๐ ๐๐ ๐๐ผ๐๐ฟ๐๐ฒ๐ ๐ช๐ถ๐๐ต ๐๐ผ๐บ๐ฝ๐น๐ฒ๐๐ถ๐ผ๐ป ๐๐ฎ๐ฑ๐ด๐ฒ๐ ๐ฅ
Google is offering free AI courses with completion badges to help students & professionals build in-demand AI skills ๐
โจ Learn from Google Experts
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โจ Build In-Demand AI Skills for 2026
๐ ๐๐ป๐ฟ๐ผ๐น๐น ๐๐ผ๐ฟ ๐๐ฅ๐๐๐:
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๐ฅ Start your AI journey today and future-proof your career with Google AI learning programs.
Google is offering free AI courses with completion badges to help students & professionals build in-demand AI skills ๐
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โจ Earn Google Completion Badges
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โค3
Want to become a pro in Data Analytics and crack interviews?
Focus on these key topics: ๐
1) Understand Data Analytics basics & tools
2) Learn Excel for data cleaning & analysis
3) Master SQL for data querying
4) Study data visualization principles
5) Get hands-on with Power BI/Tableau dashboards
6) Explore statistics & probability fundamentals
7) Learn data wrangling and preprocessing
8) Understand data storytelling and report writing
9) Practice hypothesis testing & A/B testing
10) Get familiar with Python/R for analytics (optional but helpful)
11) Work on real datasets and case studies (Kaggle is great)
12) Build end-to-end projects from data collection to visualization
13) Learn how to communicate insights effectively
14) Practice problem-solving with datasets regularly
15) Optimize your resume with analytics keywords
16) Follow analytics experts and tutorials on YouTube/LinkedIn
Pro tip: Search each topic on YouTube and watch short 10-15 min videos. Practice alongside to build strong fundamentals.
17) Finally, watch full data analytics project walkthroughs and try them yourself.
18) Learn integration of SQL and Power BI/Tableau for advanced reporting.
Credits: https://t.me/sqlspecialist
React โค๏ธ for more
Focus on these key topics: ๐
1) Understand Data Analytics basics & tools
2) Learn Excel for data cleaning & analysis
3) Master SQL for data querying
4) Study data visualization principles
5) Get hands-on with Power BI/Tableau dashboards
6) Explore statistics & probability fundamentals
7) Learn data wrangling and preprocessing
8) Understand data storytelling and report writing
9) Practice hypothesis testing & A/B testing
10) Get familiar with Python/R for analytics (optional but helpful)
11) Work on real datasets and case studies (Kaggle is great)
12) Build end-to-end projects from data collection to visualization
13) Learn how to communicate insights effectively
14) Practice problem-solving with datasets regularly
15) Optimize your resume with analytics keywords
16) Follow analytics experts and tutorials on YouTube/LinkedIn
Pro tip: Search each topic on YouTube and watch short 10-15 min videos. Practice alongside to build strong fundamentals.
17) Finally, watch full data analytics project walkthroughs and try them yourself.
18) Learn integration of SQL and Power BI/Tableau for advanced reporting.
Credits: https://t.me/sqlspecialist
React โค๏ธ for more
โค17
โ๏ธ ๐๐ถ๐ฐ๐ธ๐๐๐ฎ๐ฟ๐ ๐ฌ๐ผ๐๐ฟ ๐๐ช๐ฆ ๐๐ผ๐๐ฟ๐ป๐ฒ๐ | ๐๐ฅ๐๐ ๐๐ช๐ฆ ๐๐ฒ๐ฟ๐๐ถ๐ณ๐ถ๐ฐ๐ฎ๐๐ถ๐ผ๐ป ๐๐ผ๐๐ฟ๐๐ฒ๐๐
โ๏ธ High-Demand Cloud Skills
โ๏ธ Prepare for AWS Certifications
โ๏ธ Strengthen Your Resume & LinkedIn
โ๏ธ Unlock Opportunities in Cloud, AI & DevOps
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๐ Start Learning Today. Build Cloud Skills. Accelerate Your Tech Career!
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โ๏ธ Prepare for AWS Certifications
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๐ Start Learning Today. Build Cloud Skills. Accelerate Your Tech Career!
โค2
I see so many people jump into data analytics, excited by its popularity, only to feel lost or uninterested soon after. I get it, data isnโt for everyone, and thatโs okay.
Data analytics requires a certain spark or say curiosity. You need that drive to dig deeper, to understand why things happen, to explore how data pieces connect to reveal a bigger picture. Without that spark, itโs easy to feel overwhelmed or even bored.
Before diving in, ask yourself, Do I really enjoy solving puzzles? Am I genuinely excited about numbers, patterns, and insights? If youโre curious and love learning, data can be incredibly rewarding. But if itโs just about following a trend, it might not be a fulfilling path for you.
Be honest with yourself. Find your passion, whether itโs in data or somewhere else and invest in something that truly excites you.
Hope this helps you ๐
Data analytics requires a certain spark or say curiosity. You need that drive to dig deeper, to understand why things happen, to explore how data pieces connect to reveal a bigger picture. Without that spark, itโs easy to feel overwhelmed or even bored.
Before diving in, ask yourself, Do I really enjoy solving puzzles? Am I genuinely excited about numbers, patterns, and insights? If youโre curious and love learning, data can be incredibly rewarding. But if itโs just about following a trend, it might not be a fulfilling path for you.
Be honest with yourself. Find your passion, whether itโs in data or somewhere else and invest in something that truly excites you.
Hope this helps you ๐
โค25
๐๐ป๐๐ฒ๐ฟ๐๐ถ๐ฒ๐๐ฒ๐ฟ:
You have 2 minutes to solve this SQL query.
Find the month with the highest total sales.
Assume the table structure: sales(sale_id, sale_date, amount)
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
EXTRACT(YEAR FROM sale_date) AS year,
EXTRACT(MONTH FROM sale_date) AS month,
SUM(amount) AS total_sales
FROM sales
GROUP BY
EXTRACT(YEAR FROM sale_date),
EXTRACT(MONTH FROM sale_date)
ORDER BY total_sales DESC
LIMIT 1;
๐ก Explanation:
This query groups sales by year and month, calculates the total sales for each month, and returns the month with the highest sales.
Key parts:
โข EXTRACT YEAR FROM sale_date gets the year.
โข EXTRACT MONTH FROM sale_date gets the month.
โข SUM amount calculates total monthly sales.
โข ORDER BY total_sales DESC sorts from highest to lowest.
โข LIMIT 1 returns the top-performing month.
This question tests your understanding of:
Date Functions, Aggregate Functions SUM, GROUP BY, ORDER BY
๐ฏ Expected Output Example
Year: 2026, Month: 5, Total Sales: 245,000
๐ Alternative Handles Ties
SELECT
year,
month,
total_sales
FROM (
SELECT
EXTRACT(YEAR FROM sale_date) AS year,
EXTRACT(MONTH FROM sale_date) AS month,
SUM(amount) AS total_sales,
DENSE_RANK() OVER (
ORDER BY SUM(amount) DESC
) AS rnk
FROM sales
GROUP BY
EXTRACT(YEAR FROM sale_date),
EXTRACT(MONTH FROM sale_date)
) ranked
WHERE rnk = 1;
This version returns all months tied for the highest total sales.
๐ Date-based aggregation questions are among the most common in SQL interviews. Practice grouping data by Day, Week, Month, Quarter, Year. You'll encounter these patterns frequently in analytics and reporting roles.
โค๏ธ React with โค๏ธ for more SQL interview challenges!
You have 2 minutes to solve this SQL query.
Find the month with the highest total sales.
Assume the table structure: sales(sale_id, sale_date, amount)
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
EXTRACT(YEAR FROM sale_date) AS year,
EXTRACT(MONTH FROM sale_date) AS month,
SUM(amount) AS total_sales
FROM sales
GROUP BY
EXTRACT(YEAR FROM sale_date),
EXTRACT(MONTH FROM sale_date)
ORDER BY total_sales DESC
LIMIT 1;
๐ก Explanation:
This query groups sales by year and month, calculates the total sales for each month, and returns the month with the highest sales.
Key parts:
โข EXTRACT YEAR FROM sale_date gets the year.
โข EXTRACT MONTH FROM sale_date gets the month.
โข SUM amount calculates total monthly sales.
โข ORDER BY total_sales DESC sorts from highest to lowest.
โข LIMIT 1 returns the top-performing month.
This question tests your understanding of:
Date Functions, Aggregate Functions SUM, GROUP BY, ORDER BY
๐ฏ Expected Output Example
Year: 2026, Month: 5, Total Sales: 245,000
๐ Alternative Handles Ties
SELECT
year,
month,
total_sales
FROM (
SELECT
EXTRACT(YEAR FROM sale_date) AS year,
EXTRACT(MONTH FROM sale_date) AS month,
SUM(amount) AS total_sales,
DENSE_RANK() OVER (
ORDER BY SUM(amount) DESC
) AS rnk
FROM sales
GROUP BY
EXTRACT(YEAR FROM sale_date),
EXTRACT(MONTH FROM sale_date)
) ranked
WHERE rnk = 1;
This version returns all months tied for the highest total sales.
๐ Date-based aggregation questions are among the most common in SQL interviews. Practice grouping data by Day, Week, Month, Quarter, Year. You'll encounter these patterns frequently in analytics and reporting roles.
โค๏ธ React with โค๏ธ for more SQL interview challenges!
โค13
๐๐ณ ๐๐ฅ๐๐ ๐ ๐ถ๐ฐ๐ฟ๐ผ๐๐ผ๐ณ๐ & ๐๐ถ๐ป๐ธ๐ฒ๐ฑ๐๐ป ๐๐ฒ๐ฟ๐๐ถ๐ณ๐ถ๐ฐ๐ฎ๐๐ถ๐ผ๐ป๐ ๐
Learn job-ready skills from Microsoft + LinkedIn and add recognized certificates to your resume without spending money
โ 100% FREE to access
โ Learn from Microsoft + LinkedIn Learning
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โ Great for students, freshers, and career switchers
๐ ๐๐ป๐ฟ๐ผ๐น๐น ๐๐ผ๐ฟ ๐๐ฅ๐๐๐:
https://pdlink.in/4wmXdTY
๐ Start learning today. Collect free certifications. Build your skills. Make your resume stand out.
Learn job-ready skills from Microsoft + LinkedIn and add recognized certificates to your resume without spending money
โ 100% FREE to access
โ Learn from Microsoft + LinkedIn Learning
โ Beginner-friendly and career-focused
โ Great for students, freshers, and career switchers
๐ ๐๐ป๐ฟ๐ผ๐น๐น ๐๐ผ๐ฟ ๐๐ฅ๐๐๐:
https://pdlink.in/4wmXdTY
๐ Start learning today. Collect free certifications. Build your skills. Make your resume stand out.
โค2
๐๐ป๐๐ฒ๐ฟ๐๐ถ๐ฒ๐๐ฒ๐ฟ:
You have 2 minutes to solve this SQL query.
Find the customers who placed orders on three or more consecutive days.
Assume the table structure:
orders(order_id, customer_id, order_date)
๐ ๐ฒ: Challenge accepted! ๐ช
WITH consecutive_orders AS (
SELECT
customer_id,
order_date,
DATE_SUB(
order_date,
INTERVAL ROW_NUMBER() OVER (
PARTITION BY customer_id
ORDER BY order_date
) DAY
) AS grp
FROM (
SELECT DISTINCT
customer_id,
order_date
FROM orders
) t
)
SELECT
customer_id
FROM consecutive_orders
GROUP BY
customer_id,
grp
HAVING COUNT(*) >= 3;
๐ก Explanation:
This query identifies sequences of consecutive order dates for each customer.
โข ROW_NUMBER() assigns a sequence number to each order date per customer.
โข Subtracting the row number from the order date creates the same grp value for consecutive dates.
โข GROUP BY customer_id, grp groups each consecutive streak.
โข **HAVING COUNT(*) >= 3** returns customers with a streak of at least three consecutive days.
๐ฏ Expected Output Example
Customer ID
101
205
(Customer 101 ordered on June 1, 2, and 3. Customer 205 ordered on July 10, 11, and 12.)
๐ Tip for SQL Job Seekers:
The Gaps and Islands pattern is one of the most advanced and frequently discussed SQL interview topics. Master it for solving:
Consecutive login days, Consecutive purchases, Attendance streaks, Consecutive transactions, User activity analysis
Being comfortable with this pattern can set you apart in technical interviews.
โค๏ธ React with โค๏ธ for more SQL interview challenges!
You have 2 minutes to solve this SQL query.
Find the customers who placed orders on three or more consecutive days.
Assume the table structure:
orders(order_id, customer_id, order_date)
๐ ๐ฒ: Challenge accepted! ๐ช
WITH consecutive_orders AS (
SELECT
customer_id,
order_date,
DATE_SUB(
order_date,
INTERVAL ROW_NUMBER() OVER (
PARTITION BY customer_id
ORDER BY order_date
) DAY
) AS grp
FROM (
SELECT DISTINCT
customer_id,
order_date
FROM orders
) t
)
SELECT
customer_id
FROM consecutive_orders
GROUP BY
customer_id,
grp
HAVING COUNT(*) >= 3;
๐ก Explanation:
This query identifies sequences of consecutive order dates for each customer.
โข ROW_NUMBER() assigns a sequence number to each order date per customer.
โข Subtracting the row number from the order date creates the same grp value for consecutive dates.
โข GROUP BY customer_id, grp groups each consecutive streak.
โข **HAVING COUNT(*) >= 3** returns customers with a streak of at least three consecutive days.
๐ฏ Expected Output Example
Customer ID
101
205
(Customer 101 ordered on June 1, 2, and 3. Customer 205 ordered on July 10, 11, and 12.)
๐ Tip for SQL Job Seekers:
The Gaps and Islands pattern is one of the most advanced and frequently discussed SQL interview topics. Master it for solving:
Consecutive login days, Consecutive purchases, Attendance streaks, Consecutive transactions, User activity analysis
Being comfortable with this pattern can set you apart in technical interviews.
โค๏ธ React with โค๏ธ for more SQL interview challenges!
โค13
๐ฏ๐๐ฅ๐๐ ๐๐ป๐๐ฒ๐ฟ๐๐ถ๐ฒ๐ ๐ฃ๐ฟ๐ฒ๐ฝ๐ฎ๐ฟ๐ฎ๐๐ถ๐ผ๐ป ๐๐ผ๐๐ฟ๐๐ฒ๐ | ๐จ๐ป๐น๐ผ๐ฐ๐ธ ๐ฌ๐ผ๐๐ฟ ๐๐ฎ๐ฟ๐ฒ๐ฒ๐ฟ ๐ฃ๐ผ๐๐ฒ๐ป๐๐ถ๐ฎ๐น ๐
โ Perfect for students, freshers, and job seekers preparing for placements or their next big opportunity.
โ 100% FREE learning resources
โ Helps improve interview confidence + job readiness
โ Great for placements, internships, off-campus drives, and fresher hiring
๐ ๐๐ป๐ฟ๐ผ๐น๐น ๐๐ผ๐ฟ ๐๐ฅ๐๐๐:
https://pdlink.in/4fjeMPe
๐ Start learning today. Build confidence. Crack interviews smarter. Move closer to your dream job.
โ Perfect for students, freshers, and job seekers preparing for placements or their next big opportunity.
โ 100% FREE learning resources
โ Helps improve interview confidence + job readiness
โ Great for placements, internships, off-campus drives, and fresher hiring
๐ ๐๐ป๐ฟ๐ผ๐น๐น ๐๐ผ๐ฟ ๐๐ฅ๐๐๐:
https://pdlink.in/4fjeMPe
๐ Start learning today. Build confidence. Crack interviews smarter. Move closer to your dream job.
โค6
๐๐ป๐๐ฒ๐ฟ๐๐ถ๐ฒ๐๐ฒ๐ฟ:
You have 2 minutes to solve this SQL query.
Find the customers who placed orders on three or more consecutive days.
Assume the table structure:
orders(order_id, customer_id, order_date)
๐ ๐ฒ: Challenge accepted! ๐ช
WITH consecutive_orders AS (
SELECT
customer_id,
order_date,
DATE_SUB(
order_date,
INTERVAL ROW_NUMBER() OVER (
PARTITION BY customer_id
ORDER BY order_date
) DAY
) AS grp
FROM (
SELECT DISTINCT
customer_id,
order_date
FROM orders
) t
)
SELECT
customer_id
FROM consecutive_orders
GROUP BY
customer_id,
grp
HAVING COUNT(*) >= 3;
๐ก Explanation:
This query identifies sequences of consecutive order dates for each customer.
โข ROW_NUMBER() assigns a sequence number to each order date per customer.
โข Subtracting the row number from the order date creates the same grp value for consecutive dates.
โข GROUP BY customer_id, grp groups each consecutive streak.
โข **HAVING COUNT(*) >= 3** returns customers with a streak of at least three consecutive days.
This question tests your understanding of: Common Table Expressions (CTEs), Window Functions (ROW_NUMBER()), Gaps and Islands Problem, Date Arithmetic.
๐ฏ Expected Output Example
Customer ID
101
205
(Customer 101 ordered on June 1, 2, and 3. Customer 205 ordered on July 10, 11, and 12.)
๐ Tip for SQL Job Seekers:
The Gaps and Islands pattern is one of the most advanced and frequently discussed SQL interview topics.
Master it for solving:
โข Consecutive login days
โข Consecutive purchases
โข Attendance streaks
โข Consecutive transactions
โข User activity analysis
Being comfortable with this pattern can set you apart in technical interviews.
โค๏ธ React with โค๏ธ for more SQL interview challenges!
You have 2 minutes to solve this SQL query.
Find the customers who placed orders on three or more consecutive days.
Assume the table structure:
orders(order_id, customer_id, order_date)
๐ ๐ฒ: Challenge accepted! ๐ช
WITH consecutive_orders AS (
SELECT
customer_id,
order_date,
DATE_SUB(
order_date,
INTERVAL ROW_NUMBER() OVER (
PARTITION BY customer_id
ORDER BY order_date
) DAY
) AS grp
FROM (
SELECT DISTINCT
customer_id,
order_date
FROM orders
) t
)
SELECT
customer_id
FROM consecutive_orders
GROUP BY
customer_id,
grp
HAVING COUNT(*) >= 3;
๐ก Explanation:
This query identifies sequences of consecutive order dates for each customer.
โข ROW_NUMBER() assigns a sequence number to each order date per customer.
โข Subtracting the row number from the order date creates the same grp value for consecutive dates.
โข GROUP BY customer_id, grp groups each consecutive streak.
โข **HAVING COUNT(*) >= 3** returns customers with a streak of at least three consecutive days.
This question tests your understanding of: Common Table Expressions (CTEs), Window Functions (ROW_NUMBER()), Gaps and Islands Problem, Date Arithmetic.
๐ฏ Expected Output Example
Customer ID
101
205
(Customer 101 ordered on June 1, 2, and 3. Customer 205 ordered on July 10, 11, and 12.)
๐ Tip for SQL Job Seekers:
The Gaps and Islands pattern is one of the most advanced and frequently discussed SQL interview topics.
Master it for solving:
โข Consecutive login days
โข Consecutive purchases
โข Attendance streaks
โข Consecutive transactions
โข User activity analysis
Being comfortable with this pattern can set you apart in technical interviews.
โค๏ธ React with โค๏ธ for more SQL interview challenges!
โค8
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๐๐ป๐๐ฒ๐ฟ๐๐ถ๐ฒ๐๐ฒ๐ฟ:
You have 2 minutes to solve this SQL query.
Find the product(s) that have never been ordered.
Tables:
products(product_id, product_name)
order_details(order_id, product_id, quantity)
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
p.product_id,
p.product_name
FROM products p
LEFT JOIN order_details od
ON p.product_id = od.product_id
WHERE od.product_id IS NULL;
๐ก Explanation:
This query finds all products that do not have a matching record in the order_details table.
LEFT JOIN returns all products, regardless of whether they've been ordered. Products without matching orders will have NULL values for columns from order_details. WHERE od.product_id IS NULL filters only those products that have never been ordered.
This question tests your understanding of: LEFT JOIN, NULL handling, Finding unmatched records
๐ฏ Expected Output Example
Product ID Product Name
104 Wireless Mouse
118 USB Hub
125 Laptop Stand
๐ Alternative Using NOT EXISTS
SELECT
p.product_id,
p.product_name
FROM products p
WHERE NOT EXISTS (
SELECT 1
FROM order_details od
WHERE od.product_id = p.product_id
);
NOT EXISTS is often preferred because it handles NULL values correctly and can perform better than other approaches in many database systems.
๐ Tip for SQL Job Seekers:
Whenever you're asked to find records that don't exist in another table, consider these approaches:
LEFT JOIN ... IS NULL, NOT EXISTS โ (often the best choice), NOT IN (be cautious with NULL values)
Knowing the pros and cons of each approach is a common interview discussion point.
โค๏ธ React with โค๏ธ for more SQL interview challenges!
You have 2 minutes to solve this SQL query.
Find the product(s) that have never been ordered.
Tables:
products(product_id, product_name)
order_details(order_id, product_id, quantity)
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
p.product_id,
p.product_name
FROM products p
LEFT JOIN order_details od
ON p.product_id = od.product_id
WHERE od.product_id IS NULL;
๐ก Explanation:
This query finds all products that do not have a matching record in the order_details table.
LEFT JOIN returns all products, regardless of whether they've been ordered. Products without matching orders will have NULL values for columns from order_details. WHERE od.product_id IS NULL filters only those products that have never been ordered.
This question tests your understanding of: LEFT JOIN, NULL handling, Finding unmatched records
๐ฏ Expected Output Example
Product ID Product Name
104 Wireless Mouse
118 USB Hub
125 Laptop Stand
๐ Alternative Using NOT EXISTS
SELECT
p.product_id,
p.product_name
FROM products p
WHERE NOT EXISTS (
SELECT 1
FROM order_details od
WHERE od.product_id = p.product_id
);
NOT EXISTS is often preferred because it handles NULL values correctly and can perform better than other approaches in many database systems.
๐ Tip for SQL Job Seekers:
Whenever you're asked to find records that don't exist in another table, consider these approaches:
LEFT JOIN ... IS NULL, NOT EXISTS โ (often the best choice), NOT IN (be cautious with NULL values)
Knowing the pros and cons of each approach is a common interview discussion point.
โค๏ธ React with โค๏ธ for more SQL interview challenges!
โค8
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Interviewer:
You have 2 minutes to solve this SQL query.
Find the employee or employees with the highest salary in the company without using MAX().
Me: Challenge accepted!
Explanation:
This query finds the highest-paid employee or employees without using the MAX() aggregate function.
โข DENSE_RANK() ranks salaries in descending order.
โข The highest salary receives a rank of 1.
โข The outer query filters only employees with salary_rank = 1.
โข If multiple employees share the highest salary, they are all returned.
This question tests your understanding of:
โข Window Functions using DENSE_RANK
โข Ranking Data
โข Handling Ties
โข Alternatives to Aggregate Functions
Expected Output Example
Employee: John, Salary: 120,000
Employee: Alice, Salary: 120,000
Both employees are returned because they share the highest salary.
Alternative Solution using NOT EXISTS
This solution works by returning employees for whom no other employee has a higher salary.
Tip for SQL Job Seekers:
Interviewers often ask you to solve problems without using aggregate functions like MAX() or MIN(). Learn multiple approaches using:
โข Window Functions
โข NOT EXISTS
โข Correlated Subqueries
โข Self Joins
Demonstrating alternative solutions shows strong SQL problem-solving skills.
โค๏ธ React with โค๏ธ for more SQL interview challenges!
You have 2 minutes to solve this SQL query.
Find the employee or employees with the highest salary in the company without using MAX().
Me: Challenge accepted!
SELECT
employee_id,
employee_name,
salary
FROM (
SELECT
employee_id,
employee_name,
salary,
DENSE_RANK() OVER (ORDER BY salary DESC) AS salary_rank
FROM employees
) ranked
WHERE salary_rank = 1;
Explanation:
This query finds the highest-paid employee or employees without using the MAX() aggregate function.
โข DENSE_RANK() ranks salaries in descending order.
โข The highest salary receives a rank of 1.
โข The outer query filters only employees with salary_rank = 1.
โข If multiple employees share the highest salary, they are all returned.
This question tests your understanding of:
โข Window Functions using DENSE_RANK
โข Ranking Data
โข Handling Ties
โข Alternatives to Aggregate Functions
Expected Output Example
Employee: John, Salary: 120,000
Employee: Alice, Salary: 120,000
Both employees are returned because they share the highest salary.
Alternative Solution using NOT EXISTS
SELECT
employee_id,
employee_name,
salary
FROM employees e1
WHERE NOT EXISTS (
SELECT 1
FROM employees e2
WHERE e2.salary > e1.salary
);
This solution works by returning employees for whom no other employee has a higher salary.
Tip for SQL Job Seekers:
Interviewers often ask you to solve problems without using aggregate functions like MAX() or MIN(). Learn multiple approaches using:
โข Window Functions
โข NOT EXISTS
โข Correlated Subqueries
โข Self Joins
Demonstrating alternative solutions shows strong SQL problem-solving skills.
โค๏ธ React with โค๏ธ for more SQL interview challenges!
โค11
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Interviewer:
You have 2 minutes to solve this SQL query.
Find the employee or employees who earn more than the average salary of their department and have been with the company for more than 5 years.
Assume the table structure:
employees(employee_id, employee_name, department, salary, joining_date)
Me: Challenge accepted!
Explanation:
This query applies two conditions to identify experienced, high-performing employees.
โข The correlated subquery calculates the average salary for each employee's department.
โข The first condition returns employees earning above their department's average salary.
โข The second condition filters employees who joined the company more than 5 years ago.
โข Only employees satisfying both conditions are included in the final result.
This question tests your understanding of:
โข Correlated Subqueries
โข Aggregate Functions using AVG
โข Date Arithmetic
โข Multiple Filtering Conditions
Expected Output Example
Employee: John, Department: IT, Salary: 95,000, Joining Date: 2018-01-10
Employee: Sarah, Department: HR, Salary: 82,000, Joining Date: 2017-06-15
Alternative Using Window Functions
This approach avoids a correlated subquery by calculating the departmental average once using a window function, which can be more efficient on large datasets.
Tip for SQL Job Seekers:
Real-world interview questions often combine multiple SQL concepts in a single problem. Practice writing queries that use:
โข Window Functions
โข Correlated Subqueries
โข Date Functions
โข Aggregate Functions
โข Complex WHERE conditions
These combined-concept questions are common in mid-level and senior SQL interviews.
โค๏ธ React with โค๏ธ for more SQL interview challenges!
You have 2 minutes to solve this SQL query.
Find the employee or employees who earn more than the average salary of their department and have been with the company for more than 5 years.
Assume the table structure:
employees(employee_id, employee_name, department, salary, joining_date)
Me: Challenge accepted!
SELECT
employee_id,
employee_name,
department,
salary,
joining_date
FROM employees e
WHERE salary > (
SELECT AVG(salary)
FROM employees
WHERE department = e.department
)
AND joining_date <= CURRENT_DATE - INTERVAL '5 years';
Explanation:
This query applies two conditions to identify experienced, high-performing employees.
โข The correlated subquery calculates the average salary for each employee's department.
โข The first condition returns employees earning above their department's average salary.
โข The second condition filters employees who joined the company more than 5 years ago.
โข Only employees satisfying both conditions are included in the final result.
This question tests your understanding of:
โข Correlated Subqueries
โข Aggregate Functions using AVG
โข Date Arithmetic
โข Multiple Filtering Conditions
Expected Output Example
Employee: John, Department: IT, Salary: 95,000, Joining Date: 2018-01-10
Employee: Sarah, Department: HR, Salary: 82,000, Joining Date: 2017-06-15
Alternative Using Window Functions
SELECT
employee_id,
employee_name,
department,
salary,
joining_date
FROM (
SELECT
*,
AVG(salary) OVER (PARTITION BY department) AS dept_avg_salary
FROM employees
) e
WHERE salary > dept_avg_salary
AND joining_date <= CURRENT_DATE - INTERVAL '5 years';
This approach avoids a correlated subquery by calculating the departmental average once using a window function, which can be more efficient on large datasets.
Tip for SQL Job Seekers:
Real-world interview questions often combine multiple SQL concepts in a single problem. Practice writing queries that use:
โข Window Functions
โข Correlated Subqueries
โข Date Functions
โข Aggregate Functions
โข Complex WHERE conditions
These combined-concept questions are common in mid-level and senior SQL interviews.
โค๏ธ React with โค๏ธ for more SQL interview challenges!
โค11
Interviewer:
You have 2 minutes to solve this SQL query.
Find the employee(s) with the highest salary in each department without using window functions.
Assume the table structure:
employees(employee_id, employee_name, department, salary)
Me: Challenge accepted! ๐ช
SELECT
employee_id,
employee_name,
department,
salary
FROM employees e1
WHERE salary = (
SELECT MAX(salary)
FROM employees e2
WHERE e2.department = e1.department
);
๐ก Explanation:
This query uses a correlated subquery instead of a window function.
โข The outer query processes each employee
โข The correlated subquery finds the maximum salary within that employee's department
โข If the employee's salary matches the maximum salary, the employee is returned
โข If multiple employees share the highest salary in a department, they are all included
This question tests your understanding of:
โข Correlated Subqueries
โข Aggregate Functions (MAX)
โข Filtering with Subqueries
โข Handling Ties
๐ฏ Expected Output Example:
John | IT | 95,000
Alice | IT | 95,000
Sarah | HR | 82,000
David | Finance | 91,000
John and Alice are both returned because they share the highest salary in the IT department.
๐ Alternative Using a Self Join
SELECT
e1.employee_id,
e1.employee_name,
e1.department,
e1.salary
FROM employees e1
LEFT JOIN employees e2
ON e1.department = e2.department
AND e1.salary < e2.salary
WHERE e2.employee_id IS NULL;
This solution works by eliminating employees who have someone in the same department with a higher salary. The remaining employees are the highest-paid in their respective departments.
๐ Tip for SQL Job Seekers:
Interviewers often restrict certain SQL features like window functions or CTEs to evaluate your understanding of alternative approaches. Be prepared to solve the same problem using:
โข Correlated Subqueries
โข Self Joins
โข CTEs
โข Window Functions
Knowing multiple solutions demonstrates strong SQL fundamentals.
โค๏ธ React with โค๏ธ for more SQL interview challenges!
You have 2 minutes to solve this SQL query.
Find the employee(s) with the highest salary in each department without using window functions.
Assume the table structure:
employees(employee_id, employee_name, department, salary)
Me: Challenge accepted! ๐ช
SELECT
employee_id,
employee_name,
department,
salary
FROM employees e1
WHERE salary = (
SELECT MAX(salary)
FROM employees e2
WHERE e2.department = e1.department
);
๐ก Explanation:
This query uses a correlated subquery instead of a window function.
โข The outer query processes each employee
โข The correlated subquery finds the maximum salary within that employee's department
โข If the employee's salary matches the maximum salary, the employee is returned
โข If multiple employees share the highest salary in a department, they are all included
This question tests your understanding of:
โข Correlated Subqueries
โข Aggregate Functions (MAX)
โข Filtering with Subqueries
โข Handling Ties
๐ฏ Expected Output Example:
John | IT | 95,000
Alice | IT | 95,000
Sarah | HR | 82,000
David | Finance | 91,000
John and Alice are both returned because they share the highest salary in the IT department.
๐ Alternative Using a Self Join
SELECT
e1.employee_id,
e1.employee_name,
e1.department,
e1.salary
FROM employees e1
LEFT JOIN employees e2
ON e1.department = e2.department
AND e1.salary < e2.salary
WHERE e2.employee_id IS NULL;
This solution works by eliminating employees who have someone in the same department with a higher salary. The remaining employees are the highest-paid in their respective departments.
๐ Tip for SQL Job Seekers:
Interviewers often restrict certain SQL features like window functions or CTEs to evaluate your understanding of alternative approaches. Be prepared to solve the same problem using:
โข Correlated Subqueries
โข Self Joins
โข CTEs
โข Window Functions
Knowing multiple solutions demonstrates strong SQL fundamentals.
โค๏ธ React with โค๏ธ for more SQL interview challenges!
โค5๐4
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๐๐ป๐๐ฒ๐ฟ๐๐ถ๐ฒ๐๐ฒ๐ฟ:
You have 2 minutes to solve this SQL query.
Find the second most recent order placed by each customer.
Assume the table structure:
orders(order_id, customer_id, order_date)
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
order_id,
customer_id,
order_date
FROM (
SELECT
order_id,
customer_id,
order_date,
ROW_NUMBER() OVER (
PARTITION BY customer_id
ORDER BY order_date DESC
) AS rn
FROM orders
) ranked
WHERE rn = 2;
๐ก Explanation:
The query assigns a rank to each order based on its order date for every customer.
โข PARTITION BY customer_id creates a separate ranking for each customer
โข ORDER BY order_date DESC ranks the most recent order as 1
โข ROW_NUMBER() ensures each order gets a unique rank
โข The outer query returns only the order with rn = 2, i.e., the second most recent order
This question tests your understanding of:
โ Window Functions (ROW_NUMBER)
โ Ranking Records
โ Partitioning Data
โ Top N per Group
๐ฏ Expected Output Example
Customer ID | Order ID | Order Date
101 | 2056 | 2026-06-15
102 | 2074 | 2026-06-18
Customers with fewer than two orders are automatically excluded.
๐ Alternative Using a Correlated Subquery
SELECT
o1.order_id,
o1.customer_id,
o1.order_date
FROM orders o1
WHERE 1 = (
SELECT COUNT(*)
FROM orders o2
WHERE o2.customer_id = o1.customer_id
AND o2.order_date > o1.order_date
);
This approach counts how many orders are more recent than the current order. If exactly one order is more recent, the current order is the second most recent.
๐ Tip for SQL Job Seekers:
Questions involving the Nth latest or Nth earliest record appear frequently in interviews. Practice solving them using:
โข ROW_NUMBER()
โข RANK()
โข DENSE_RANK()
โข Correlated Subqueries
Understanding when to use each approach is a valuable interview skill.
โค๏ธ React with โค๏ธ for more interview challenges!
You have 2 minutes to solve this SQL query.
Find the second most recent order placed by each customer.
Assume the table structure:
orders(order_id, customer_id, order_date)
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
order_id,
customer_id,
order_date
FROM (
SELECT
order_id,
customer_id,
order_date,
ROW_NUMBER() OVER (
PARTITION BY customer_id
ORDER BY order_date DESC
) AS rn
FROM orders
) ranked
WHERE rn = 2;
๐ก Explanation:
The query assigns a rank to each order based on its order date for every customer.
โข PARTITION BY customer_id creates a separate ranking for each customer
โข ORDER BY order_date DESC ranks the most recent order as 1
โข ROW_NUMBER() ensures each order gets a unique rank
โข The outer query returns only the order with rn = 2, i.e., the second most recent order
This question tests your understanding of:
โ Window Functions (ROW_NUMBER)
โ Ranking Records
โ Partitioning Data
โ Top N per Group
๐ฏ Expected Output Example
Customer ID | Order ID | Order Date
101 | 2056 | 2026-06-15
102 | 2074 | 2026-06-18
Customers with fewer than two orders are automatically excluded.
๐ Alternative Using a Correlated Subquery
SELECT
o1.order_id,
o1.customer_id,
o1.order_date
FROM orders o1
WHERE 1 = (
SELECT COUNT(*)
FROM orders o2
WHERE o2.customer_id = o1.customer_id
AND o2.order_date > o1.order_date
);
This approach counts how many orders are more recent than the current order. If exactly one order is more recent, the current order is the second most recent.
๐ Tip for SQL Job Seekers:
Questions involving the Nth latest or Nth earliest record appear frequently in interviews. Practice solving them using:
โข ROW_NUMBER()
โข RANK()
โข DENSE_RANK()
โข Correlated Subqueries
Understanding when to use each approach is a valuable interview skill.
โค๏ธ React with โค๏ธ for more interview challenges!
โค5๐3