اکنون در دسترس! پژوهش تلگرام ۲۰۲۵ — مهمترین بینشهای سال 
SQL Programming Resources
رفتن به کانال در Telegram
Find top SQL resources from global universities, cool projects, and learning materials for data analytics. Admin: @coderfun Useful links: heylink.me/DataAnalytics Promotions: @love_data
نمایش بیشتر📈 تحلیل کانال تلگرام SQL Programming Resources
کانال SQL Programming Resources (@sqlanalyst) در بخش زبانی انگلیسی بازیگری فعال است. در حال حاضر جامعه شامل 75 988 مشترک است و جایگاه 1 692 را در دسته فناوری و برنامهها و رتبه 4 136 را در منطقه الهند دارد.
📊 شاخصهای مخاطب و پویایی
از زمان ایجاد در невідомо، پروژه رشد سریعی داشته و 75 988 مشترک جذب کرده است.
بر اساس آخرین دادهها در تاریخ 28 ژوئن, 2026، کانال فعالیت پایداری دارد. در ۳۰ روز گذشته تغییر اعضا برابر 373 و در ۲۴ ساعت گذشته برابر -10 بوده و همچنان دسترسی گستردهای حفظ شده است.
- وضعیت تأیید: تأیید نشده
- نرخ تعامل (ER): میانگین تعامل مخاطب 2.35% است و در ۲۴ ساعت نخست پس از انتشار، محتوا معمولاً 1.03% واکنش نسبت به کل مشترکان کسب میکند.
- دسترسی پستها: هر پست به طور میانگین 1 783 بازدید دریافت میکند. در اولین روز معمولاً 786 بازدید جمعآوری میشود.
- واکنشها و تعامل: مخاطبان بهطور فعال حمایت میکنند؛ میانگین واکنش به هر پست 3 است.
- علایق موضوعی: محتوا بر موضوعات کلیدی مانند row, sql, customer_id, logic, desc تمرکز دارد.
📝 توضیح و سیاست محتوایی
نویسنده این فضا را محل بیان دیدگاههای شخصی توصیف میکند:
“Find top SQL resources from global universities, cool projects, and learning materials for data analytics.
Admin: @coderfun
Useful links: heylink.me/DataAnalytics
Promotions: @love_data”
به لطف بهروزرسانیهای پرتکرار (آخرین داده در تاریخ 29 ژوئن, 2026)، کانال همواره بهروز و دارای دسترسی بالاست. تحلیلها نشان میدهد مخاطبان بهطور فعال با محتوا تعامل دارند و آن را به نقطه اثرگذاری مهم در دسته فناوری و برنامهها تبدیل کردهاند.
75 988
مشترکین
-1024 ساعت
+397 روز
+37330 روز
در حال بارگیری داده...
کانالهای مشابه
74.8K
56.1K
52.1K
47.4K
6.3K
1
ابر برچسبها
اشارات ورودی و خروجی
---
---
---
---
---
---
جذب مشترکین
ژوئن '26
ژوئن '26
+499
در 8 کانالها
مه '26
+597
در 9 کانالها
Get PRO
آوریل '26
+494
در 4 کانالها
Get PRO
مارس '26
+166
در 6 کانالها
Get PRO
فوریه '26
+741
در 13 کانالها
Get PRO
ژانویه '26
+716
در 5 کانالها
Get PRO
دسامبر '25
+863
در 4 کانالها
Get PRO
نوامبر '25
+771
در 6 کانالها
Get PRO
اکتبر '25
+676
در 4 کانالها
Get PRO
سپتامبر '25
+468
در 12 کانالها
Get PRO
اوت '25
+502
در 25 کانالها
Get PRO
ژوئیه '25
+625
در 21 کانالها
Get PRO
ژوئن '25
+1 033
در 37 کانالها
Get PRO
مه '25
+2 110
در 26 کانالها
Get PRO
آوریل '25
+3 784
در 40 کانالها
Get PRO
مارس '25
+1 190
در 27 کانالها
Get PRO
فوریه '25
+881
در 30 کانالها
Get PRO
ژانویه '25
+1 239
در 36 کانالها
Get PRO
دسامبر '24
+1 240
در 22 کانالها
Get PRO
نوامبر '24
+3 503
در 23 کانالها
Get PRO
اکتبر '24
+3 975
در 29 کانالها
Get PRO
سپتامبر '24
+4 469
در 26 کانالها
Get PRO
اوت '24
+5 990
در 23 کانالها
Get PRO
ژوئیه '24
+8 180
در 25 کانالها
Get PRO
ژوئن '24
+7 119
در 22 کانالها
Get PRO
مه '24
+5 879
در 12 کانالها
Get PRO
آوریل '24
+5 286
در 13 کانالها
Get PRO
مارس '24
+6 156
در 17 کانالها
Get PRO
فوریه '24
+4 581
در 8 کانالها
Get PRO
ژانویه '24
+5 285
در 4 کانالها
Get PRO
دسامبر '23
+7 504
در 8 کانالها
| تاریخ | رشد مشترکین | اشارات | کانالها | |
| 28 ژوئن | +2 | |||
| 27 ژوئن | +14 | |||
| 26 ژوئن | +14 | |||
| 25 ژوئن | +25 | |||
| 24 ژوئن | +34 | |||
| 23 ژوئن | +9 | |||
| 22 ژوئن | +1 | |||
| 21 ژوئن | 0 | |||
| 20 ژوئن | 0 | |||
| 19 ژوئن | 0 | |||
| 18 ژوئن | +9 | |||
| 17 ژوئن | +1 | |||
| 16 ژوئن | +21 | |||
| 15 ژوئن | +17 | |||
| 14 ژوئن | +25 | |||
| 13 ژوئن | +39 | |||
| 12 ژوئن | +32 | |||
| 11 ژوئن | +21 | |||
| 10 ژوئن | +19 | |||
| 09 ژوئن | +15 | |||
| 08 ژوئن | +7 | |||
| 07 ژوئن | +24 | |||
| 06 ژوئن | +10 | |||
| 05 ژوئن | +48 | |||
| 04 ژوئن | +62 | |||
| 03 ژوئن | +28 | |||
| 02 ژوئن | +18 | |||
| 01 ژوئن | +4 |
پستهای کانال
𝗧𝗖𝗦 𝗙𝗥𝗘𝗘 𝗖𝗲𝗿𝘁𝗶𝗳𝗶𝗰𝗮𝘁𝗶𝗼𝗻 𝗢𝗻 𝗗𝗮𝘁𝗮 𝗠𝗮𝗻𝗮𝗴𝗲𝗺𝗲𝗻𝘁 - 𝗘𝗻𝗿𝗼𝗹𝗹 𝗙𝗼𝗿 𝗙𝗥𝗘𝗘😍
TCS iON is offering a FREE Master Data Management Course with a Certificate,
✅ 100% FREE Learning
✅ Certificate on Completion
✅ Self-Paced Online Course
✅ Beginner-Friendly Content
✅ Industry-Relevant Skills
✅ Resume & LinkedIn Profile Boost
🔗 𝗘𝗻𝗿𝗼𝗹𝗹 𝗙𝗼𝗿 𝗙𝗥𝗘𝗘👇:
https://pdlink.in/4jGFBw0
🚀 Start Learning Today. Upskill for Free. Get Career Ready!
| 2 | 🚀 SQL Business Scenario Interview Questions with Answers Part 6
📌 Question 51: Find Customers Who Haven't Ordered in the Last 90 Days
Tables: customers (customer_id), orders (customer_id, order_date)
SELECT c.customer_id
FROM customers c
LEFT JOIN orders o
ON c.customer_id = o.customer_id
GROUP BY c.customer_id
HAVING MAX(order_date) < CURRENT_DATE - INTERVAL '90 days'
OR MAX(order_date) IS NULL;
📌 Question 52: Calculate Average Revenue Per User ARPU
Tables: users (user_id), orders (user_id, amount)
SELECT
ROUND(
SUM(amount) * 1.0 /
COUNT(DISTINCT u.user_id),
2
) AS arpu
FROM users u
LEFT JOIN orders o
ON u.user_id = o.user_id;
📌 Question 53: Find the Fastest Selling Product
Table: inventory (product_id, launch_date)
Table: sales (product_id, sale_date)
Requirement: Find the product with the fewest days from launch to first sale.
WITH first_sale AS (
SELECT
product_id,
MIN(sale_date) AS first_sale_date
FROM sales
GROUP BY product_id
)
SELECT
i.product_id,
(first_sale_date - launch_date) AS days_to_sell
FROM inventory i
JOIN first_sale f
ON i.product_id = f.product_id
ORDER BY days_to_sell
LIMIT 1;
📌 Question 54: Find Customers Who Purchased in Every Quarter
Table: orders (customer_id, order_date)
WITH customer_quarters AS (
SELECT
customer_id,
COUNT(
DISTINCT DATE_TRUNC('quarter', order_date)
) AS quarter_count
FROM orders
GROUP BY customer_id
),
total_quarters AS (
SELECT COUNT(
DISTINCT DATE_TRUNC('quarter', order_date)
) AS total_quarters
FROM orders
)
SELECT customer_id
FROM customer_quarters
CROSS JOIN total_quarters
WHERE quarter_count = total_quarters;
📌 Question 55: Find Revenue Contribution of Top 10 Customers
Table: orders (customer_id, amount)
WITH customer_revenue AS (
SELECT
customer_id,
SUM(amount) AS revenue
FROM orders
GROUP BY customer_id
)
SELECT
SUM(revenue) AS top10_revenue,
ROUND(
100.0 * SUM(revenue) /
(
SELECT SUM(amount)
FROM orders
),
2
) AS contribution_pct
FROM (
SELECT revenue
FROM customer_revenue
ORDER BY revenue DESC
LIMIT 10
) t;
📌 Question 56: Find Products Never Returned
Tables:
products (product_id)
sales (order_id, product_id)
returns (order_id)
SELECT DISTINCT
p.product_id
FROM products p
LEFT JOIN sales s
ON p.product_id = s.product_id
LEFT JOIN returns r
ON s.order_id = r.order_id
WHERE r.order_id IS NULL;
📌 Question 57: Calculate Daily Revenue Growth
Table: sales (sale_date, amount)
WITH daily_sales AS (
SELECT
sale_date,
SUM(amount) AS revenue
FROM sales
GROUP BY sale_date
)
SELECT
sale_date,
revenue,
ROUND(
100.0 *
(
revenue -
LAG(revenue) OVER(
ORDER BY sale_date
)
/
LAG(revenue) OVER(
ORDER BY sale_date
),
2
) AS growth_pct
FROM daily_sales;
📌 Question 58: Find the Most Loyal Customers
Table: orders (customer_id, order_date)
Requirement: Customers who placed orders in the highest number of distinct months.
SELECT
customer_id,
COUNT(
DISTINCT DATE_TRUNC('month', order_date)
) AS active_months
FROM orders
GROUP BY customer_id
ORDER BY active_months DESC
LIMIT 10;
📌 Question 59: Find Products With Zero Sales
Tables:
products (product_id)
sales (product_id)
SELECT
p.product_id
FROM products p
LEFT JOIN sales s
ON p.product_id = s.product_id
WHERE s.product_id IS NULL;
📌 Question 60: Calculate Average Orders Per Customer
Table: orders (customer_id)
SELECT
ROUND(
COUNT(*) * 1.0 /
COUNT(DISTINCT customer_id),
2
) AS avg_orders_per_customer
FROM orders;
❤️ Double Tap For More | 666 |
| 3 |  📊 𝗙𝗥𝗘𝗘 𝗗𝗮𝘁𝗮 𝗔𝗻𝗮𝗹𝘆𝘁𝗶𝗰𝘀 𝗖𝗼𝘂𝗿𝘀𝗲𝘀 | 𝗡𝗼 𝗘𝘅𝗽𝗲𝗿𝗶𝗲𝗻𝗰𝗲 𝗡𝗲𝗲𝗱𝗲𝗱! 🚀
Want to start a career in Data Analytics but don't know where to begin?
These 5 FREE beginner-friendly courses will help you learn the most in-demand data skills and build a strong foundation.
🔗 𝗘𝗻𝗿𝗼𝗹𝗹 𝗙𝗼𝗿 𝗙𝗥𝗘𝗘👇:
https://pdlink.in/3SOk64h
🚀 Start Learning Today. Build Your Portfolio. Land Your Dream Data Job! | 749 |
| 4 | 🚀 SQL Scenario Based Interview Questions with Answers: Part-5
📌 Question 41: Find Customers Whose Spending Decreased for 3 Consecutive Months
Table: orders (customer_id, amount, order_date)
WITH monthly_spend AS (
SELECT
customer_id,
DATE_TRUNC('month', order_date) AS month,
SUM(amount) AS revenue
FROM orders
GROUP BY customer_id, DATE_TRUNC('month', order_date)
),
spend_trend AS (
SELECT *,
LAG(revenue,1) OVER(PARTITION BY customer_id ORDER BY month) AS prev1,
LAG(revenue,2) OVER(PARTITION BY customer_id ORDER BY month) AS prev2
FROM monthly_spend
)
SELECT customer_id, month
FROM spend_trend
WHERE revenue < prev1
AND prev1 < prev2;
📌 Question 42: Find the Median Order Amount for Each Month
Table: orders (order_id, amount, order_date)
SELECT
DATE_TRUNC('month', order_date) AS month,
PERCENTILE_CONT(0.5)
WITHIN GROUP (ORDER BY amount) AS median_order
FROM orders
GROUP BY DATE_TRUNC('month', order_date);
📌 Question 43: Find Customers Who Ordered on Every Weekend
Table: orders (customer_id, order_date)
SELECT
customer_id
FROM orders
WHERE EXTRACT(DOW FROM order_date) IN (0,6)
GROUP BY customer_id
HAVING COUNT(DISTINCT order_date) >= 8;
📌 Question 44: Find the Top 5% Highest Revenue Customers
Table: orders (customer_id, amount)
WITH revenue AS (
SELECT
customer_id,
SUM(amount) AS total_revenue
FROM orders
GROUP BY customer_id
)
SELECT *
FROM (
SELECT *,
NTILE(20) OVER (ORDER BY total_revenue DESC) AS bucket
FROM revenue
) t
WHERE bucket = 1;
📌 Question 45: Find the Most Frequently Returned Product
Tables:
sales (order_id, product_id)
returns (order_id)
SELECT
s.product_id,
COUNT(*) AS return_count
FROM sales s
JOIN returns r
ON s.order_id = r.order_id
GROUP BY s.product_id
ORDER BY return_count DESC
LIMIT 1;
📌 Question 46: Calculate Average Delivery Time
Table: deliveries (order_id, order_date, delivery_date)
SELECT
ROUND(
AVG(delivery_date - order_date),
2
) AS avg_delivery_days
FROM deliveries;
📌 Question 47: Find Users Who Logged In Every Day Last Week
Table: logins (user_id, login_date)
SELECT
user_id
FROM logins
WHERE login_date >= CURRENT_DATE - INTERVAL '6 day'
GROUP BY user_id
HAVING COUNT(DISTINCT login_date) = 7;
📌 Question 48: Find Products with Revenue Above Category Average
Tables:
products (product_id, category)
sales (product_id, amount)
WITH product_revenue AS (
SELECT
p.product_id,
p.category,
SUM(s.amount) AS revenue
FROM products p
JOIN sales s
ON p.product_id = s.product_id
GROUP BY p.product_id, p.category
)
SELECT *
FROM (
SELECT *,
AVG(revenue) OVER (
PARTITION BY category
) AS category_avg
FROM product_revenue
) t
WHERE revenue > category_avg;
📌 Question 49: Find the Busiest Day of the Week
Table: orders (order_date)
SELECT
TO_CHAR(order_date, 'Day') AS weekday,
COUNT(*) AS total_orders
FROM orders
GROUP BY weekday
ORDER BY total_orders DESC
LIMIT 1;
📌 Question 50: Calculate Customer Retention After First Purchase
Table: orders (customer_id, order_date)
WITH customer_orders AS (
SELECT
customer_id,
COUNT() AS total_orders
FROM orders
GROUP BY customer_id
)
SELECT
ROUND(
100.0 *
COUNT(CASE WHEN total_orders > 1 THEN 1 END)
/ COUNT(),
2
) AS retention_rate
FROM customer_orders;
🎯 Concepts Covered:
✅ Window Functions
✅ Percentiles
✅ NTILE()
✅ Retention Analysis
✅ Revenue Analytics
✅ Delivery KPIs
✅ Customer Behavior Analysis
✅ Advanced Business SQL
❤️ Double Tap For More | 1 031 |
| 5 |  📊 𝗙𝗥𝗘𝗘 𝗧𝗮𝘁𝗮 𝗗𝗮𝘁𝗮 𝗔𝗻𝗮𝗹𝘆𝘁𝗶𝗰𝘀 𝗩𝗶𝗿𝘁𝘂𝗮𝗹 𝗜𝗻𝘁𝗲𝗿𝗻𝘀𝗵𝗶𝗽 | 𝗪𝗶𝘁𝗵 𝗖𝗲𝗿𝘁𝗶𝗳𝗶𝗰𝗮𝘁𝗲 🚀
Here's an amazing opportunity to complete the FREE Tata Data Analytics Virtual Internship and earn a certificate that you can showcase on your Resume and LinkedIn.
✅ 100% FREE
✅ Self-Paced & Online
✅ Beginner-Friendly
✅ Certificate on Completion
✅ Real Business Case Studies
✅ Resume & LinkedIn Boost
🔗 𝗘𝗻𝗿𝗼𝗹𝗹 𝗙𝗼𝗿 𝗙𝗥𝗘𝗘👇:
https://pdlink.in/4eybW8J
🚀 Upskill Today. Build Your Portfolio. Get Career Ready! | 1 170 |
| 6 | SELECT
EXTRACT(HOUR FROM order_timestamp) AS order_hour,
COUNT(*) AS total_orders
FROM orders
GROUP BY order_hour
ORDER BY total_orders DESC
LIMIT 1;
📌 Question 40: Rank Salespersons by Quarterly Revenue
Table: sales salesperson_id, amount, sale_date
WITH quarterly_sales AS (
SELECT
salesperson_id,
DATE_TRUNC('quarter', sale_date) AS quarter,
SUM(amount) AS revenue
FROM sales
GROUP BY 1,2
)
SELECT *,
DENSE_RANK() OVER (
PARTITION BY quarter
ORDER BY revenue DESC
) AS sales_rank
FROM quarterly_sales;
Double Tap ❤️ For More | 1 315 |
| 7 | SELECT
EXTRACT(HOUR FROM order_timestamp) AS order_hour,
COUNT(*) AS total_orders
FROM orders
GROUP BY order_hour
ORDER BY total_orders DESC
LIMIT 1;
📌 Question 40: Rank Salespersons by Quarterly Revenue
Table: sales salesperson_id, amount, sale_date
WITH quarterly_sales AS (
SELECT
salesperson_id,
DATE_TRUNC('quarter', sale_date) AS quarter,
SUM(amount) AS revenue
FROM sales
GROUP BY 1,2
)
SELECT *,
DENSE_RANK() OVER (
PARTITION BY quarter
ORDER BY revenue DESC
) AS sales_rank
FROM quarterly_sales;
Double Tap ❤️ For More
-----
1.38 ₽ · /balance_help | 1 |
| 8 | 🚀 SQL Scenario Based Interview Questions with Answers Part 4
📌 Question 31: Find Customers Who Increased Their Monthly Spending
Table: orders customer_id, amount, order_date
Requirement: Return customers whose spending increased compared to the previous month.
WITH monthly_spend AS (
SELECT
customer_id,
DATE_TRUNC('month', order_date) AS month,
SUM(amount) AS total_spend
FROM orders
GROUP BY customer_id, DATE_TRUNC('month', order_date)
)
SELECT
customer_id,
month,
total_spend
FROM (
SELECT *,
LAG(total_spend) OVER (
PARTITION BY customer_id
ORDER BY month
) AS prev_spend
FROM monthly_spend
) t
WHERE total_spend > prev_spend;
📌 Question 32: Find Products Purchased Together Most Often
Table: order_items order_id, product_id
SELECT
a.product_id AS product_1,
b.product_id AS product_2,
COUNT(*) AS frequency
FROM order_items a
JOIN order_items b
ON a.order_id = b.order_id
AND a.product_id < b.product_id
GROUP BY 1,2
ORDER BY frequency DESC
LIMIT 10;
📌 Question 33: Find Users Active for 7 Consecutive Days
Table: user_activity user_id, activity_date
WITH activity AS (
SELECT
user_id,
activity_date,
activity_date -
ROW_NUMBER() OVER (
PARTITION BY user_id
ORDER BY activity_date
) * INTERVAL '1 day' AS grp
FROM user_activity
)
SELECT
user_id
FROM activity
GROUP BY user_id, grp
HAVING COUNT(*) >= 7;
📌 Question 34: Calculate Repeat Purchase Rate
Table: orders customer_id, order_id
SELECT
ROUND(
100.0 *
COUNT(CASE WHEN order_count > 1 THEN 1 END) /
COUNT(*),
2
) AS repeat_purchase_rate
FROM (
SELECT
customer_id,
COUNT(*) AS order_count
FROM orders
GROUP BY customer_id
) t;
📌 Question 35: Find the Longest Gap Between Two Orders
Table: orders customer_id, order_date
WITH gaps AS (
SELECT
customer_id,
order_date,
order_date -
LAG(order_date) OVER (
PARTITION BY customer_id
ORDER BY order_date
) AS gap_days
FROM orders
)
SELECT
customer_id,
MAX(gap_days) AS longest_gap
FROM gaps
GROUP BY customer_id;
📌 Question 36: Calculate Revenue Lost Due to Churn
Tables: customers customer_id, status, orders customer_id, amount
SELECT
SUM(amount) AS churned_revenue
FROM customers c
JOIN orders o
ON c.customer_id = o.customer_id
WHERE c.status = 'Churned';
📌 Question 37: Find the Fastest Growing Product
Table: sales product_id, amount, sale_date
WITH monthly_sales AS (
SELECT
product_id,
DATE_TRUNC('month', sale_date) AS month,
SUM(amount) AS revenue
FROM sales
GROUP BY 1,2
)
SELECT *
FROM (
SELECT *,
revenue -
LAG(revenue) OVER (
PARTITION BY product_id
ORDER BY month
) AS growth
FROM monthly_sales
) t
ORDER BY growth DESC
LIMIT 1;
📌 Question 38: Find Customers Who Purchased Every Product Category
Tables: products product_id, category, orders customer_id, product_id
SELECT
customer_id
FROM orders o
JOIN products p
ON o.product_id = p.product_id
GROUP BY customer_id
HAVING COUNT(DISTINCT category) = (
SELECT COUNT(DISTINCT category)
FROM products
);
📌 Question 39: Find Peak Ordering Hour
Table: orders order_id, order_timestamp | 1 066 |
| 9 |  📊 𝗣𝘄𝗖 𝗶𝘀 𝗼𝗳𝗳𝗲𝗿𝗶𝗻𝗴 𝗮 𝗙𝗥𝗘𝗘 𝗣𝗼𝘄𝗲𝗿 𝗕𝗜 𝗖𝗲𝗿𝘁𝗶𝗳𝗶𝗰𝗮𝘁𝗶𝗼𝗻 𝗣𝗿𝗼𝗴𝗿𝗮𝗺
This helps tolearn data visualization, dashboard creation, KPI analysis, and business intelligence skills that companies actively look for.
✅ Free Certificate
✅ Self-Paced Learning
✅ Hands-On Power BI Projects
✅ Beginner Friendly
✅ Resume & LinkedIn Boost
Don't miss this opportunity to add an in-demand skill to your profile and stand out from the crowd! 💼🔥
🔗 𝗘𝗻𝗿𝗼𝗹𝗹 𝗙𝗼𝗿 𝗙𝗥𝗘𝗘👇:
https://pdlink.in/4g5sKFa
Share with yours friends who wants to start a career in Data Analytics | 1 007 |
| 10 | 🚀 SQL Scenario Based Interview Questions with Answers: Part-3
📌 Question 21: Find the First Purchase Date for Every Customer
Table: orders order_id, customer_id, order_date
SELECT
customer_id,
MIN(order_date) AS first_purchase_date
FROM orders
GROUP BY customer_id;
📌 Question 22: Calculate Customer Lifetime Value (CLV)
Table: orders customer_id, amount
Requirement: Total revenue generated by each customer.
SELECT
customer_id,
SUM(amount) AS lifetime_value
FROM orders
GROUP BY customer_id
ORDER BY lifetime_value DESC;
📌 Question 23: Find the Top 5 Products Contributing 80% of Revenue
Table: sales product_id, amount
WITH product_revenue AS (
SELECT
product_id,
SUM(amount) AS revenue
FROM sales
GROUP BY product_id
),
revenue_rank AS (
SELECT
product_id,
revenue,
SUM(revenue) OVER (ORDER BY revenue DESC) AS running_revenue,
SUM(revenue) OVER () AS total_revenue
FROM product_revenue
)
SELECT
product_id,
revenue,
ROUND(100.0 * running_revenue / total_revenue, 2) AS cumulative_pct
FROM revenue_rank
WHERE running_revenue <= total_revenue * 0.80;
📌 Question 24: Find Customers Who Purchased More Than 3 Different Products
Table: orders customer_id, product_id
SELECT
customer_id
FROM orders
GROUP BY customer_id
HAVING COUNT(DISTINCT product_id) > 3;
📌 Question 25: Find the Highest Revenue Order for Each Customer
Table: orders order_id, customer_id, amount
WITH ranked_orders AS (
SELECT *,
ROW_NUMBER() OVER (
PARTITION BY customer_id
ORDER BY amount DESC
) AS rn
FROM orders
)
SELECT
customer_id,
order_id,
amount
FROM ranked_orders
WHERE rn = 1;
📌 Question 26: Calculate Average Time Between Orders
Table: orders customer_id, order_date
WITH order_gap AS (
SELECT
customer_id,
order_date,
LAG(order_date) OVER (
PARTITION BY customer_id
ORDER BY order_date
) AS previous_order
FROM orders
)
SELECT
customer_id,
AVG(order_date - previous_order) AS avg_days_between_orders
FROM order_gap
WHERE previous_order IS NOT NULL
GROUP BY customer_id;
📌 Question 27: Find Users Who Abandoned Their Cart
Tables: cart user_id, product_id, orders user_id
Requirement: Users who added items to their cart but never completed a purchase.
SELECT DISTINCT
c.user_id
FROM cart c
LEFT JOIN orders o
ON c.user_id = o.user_id
WHERE o.user_id IS NULL;
📌 Question 28: Find Revenue Generated by New vs Returning Customers
Tables: users user_id, signup_date, orders user_id, amount, order_date
SELECT
CASE
WHEN DATE_TRUNC('month', signup_date) =
DATE_TRUNC('month', order_date)
THEN 'New'
ELSE 'Returning'
END AS customer_type,
SUM(amount) AS revenue
FROM users u
JOIN orders o
ON u.user_id = o.user_id
GROUP BY customer_type;
📌 Question 29: Find the Most Frequently Purchased Product Pair
Table: order_items order_id, product_id
SELECT
a.product_id AS product_1,
b.product_id AS product_2,
COUNT(*) AS pair_count
FROM order_items a
JOIN order_items b
ON a.order_id = b.order_id
AND a.product_id < b.product_id
GROUP BY
a.product_id,
b.product_id
ORDER BY pair_count DESC
LIMIT 1;
📌 Question 30: Calculate Revenue Contribution by Region
Tables: customers customer_id, region, orders customer_id, amount
SELECT
c.region,
SUM(o.amount) AS revenue,
ROUND(
100.0 * SUM(o.amount) /
SUM(SUM(o.amount)) OVER (),
2
) AS revenue_share
FROM customers c
JOIN orders o
ON c.customer_id = o.customer_id
GROUP BY c.region
ORDER BY revenue DESC;
Double Tap ❤️ For More | 1 144 |
| 11 |  𝗠𝗶𝗰𝗿𝗼𝘀𝗼𝗳𝘁 𝟭𝟬𝟬+ 𝗙𝗥𝗘𝗘 𝗖𝗼𝘂𝗿𝘀𝗲𝘀 𝗳𝗼𝗿 𝗔𝘇𝘂𝗿𝗲, 𝗔𝗜, 𝗖𝘆𝗯𝗲𝗿𝘀𝗲𝗰𝘂𝗿𝗶𝘁𝘆 & 𝗠𝗼𝗿𝗲 🚀
Learn the most in-demand tech skills from Microsoft completely FREE🌟
Microsoft Learn offers 100+ free courses designed to help students, freshers, and professionals build job-ready skills in today's fastest-growing technology domains.
✅ 100% Free Learning
✅ Beginner to Advanced Levels
🔗 𝗘𝗻𝗿𝗼𝗹𝗹 𝗙𝗼𝗿 𝗙𝗥𝗘𝗘👇:
https://pdlink.in/4f0GNuH
🚀 Learn. Practice. Upskill. Get Career Ready | 1 061 |
| 12 |  𝗦𝗤𝗟 𝗠𝘂𝘀𝘁-𝗞𝗻𝗼𝘄 𝗗𝗶𝗳𝗳𝗲𝗿𝗲𝗻𝗰𝗲𝘀 📊
Whether you're writing daily queries or preparing for interviews, understanding these subtle SQL differences can make a big impact on both performance and accuracy.
🧠 Here’s a powerful visual that compares the most commonly misunderstood SQL concepts — side by side.
📌 𝗖𝗼𝘃𝗲𝗿𝗲𝗱 𝗶𝗻 𝘁𝗵𝗶𝘀 𝘀𝗻𝗮𝗽𝘀𝗵𝗼𝘁:
🔹 RANK() vs DENSE_RANK()
🔹 HAVING vs WHERE
🔹 UNION vs UNION ALL
🔹 JOIN vs UNION
🔹 CTE vs TEMP TABLE
🔹 SUBQUERY vs CTE
🔹 ISNULL vs COALESCE
🔹 DELETE vs DROP
🔹 INTERSECT vs INNER JOIN
🔹 EXCEPT vs NOT IN
React ♥️ for detailed post with examples | 1 351 |
| 13 |  🎓 𝗚𝗼𝗼𝗴𝗹𝗲 𝗙𝗥𝗘𝗘 𝗖𝗲𝗿𝘁𝗶𝗳𝗶𝗰𝗮𝘁𝗶𝗼𝗻 𝗖𝗼𝘂𝗿𝘀𝗲𝘀 𝟮𝟬𝟮𝟲 🚀
Learn job-ready skills from Google and boost your resume?🌟
✔️ Learn from Google Experts
✔️ Industry-Recognized Certificates
✔️ Beginner-Friendly Learning Paths
✔️ Self-Paced Courses
✔️ Enhance Resume & LinkedIn Profile
✔️ Build Job-Ready Skills
🔗 𝗘𝗻𝗿𝗼𝗹𝗹 𝗙𝗼𝗿 𝗙𝗥𝗘𝗘👇:
https://pdlink.in/4vjLGVq
⏳ Start Learning Today & Upgrade Your Career! | 1 546 |
| 14 | ✅ SQL Interview Questions with Answers
1. What is a window function?
A window function computes results over a group ("window") of rows related to the current row, without collapsing them (like GROUP BY).
Examples: ROW_NUMBER(), RANK(), SUM() OVER(...) for running totals, rankings, or moving averages.
2. What is the difference between RANK() and ROW_NUMBER()?
• ROW_NUMBER(): assigns unique sequential numbers to all rows, even if values are equal.
• RANK(): gives same rank to tied values, then skips the next rank (e.g., 1, 1, 3).
3. How do you find the second highest salary?
SELECT salary
FROM (
SELECT salary, DENSE_RANK() OVER (ORDER BY salary DESC) as rnk
FROM employees
) t
WHERE rnk = 2;
This avoids ties if you want exactly the second‑highest value.
4. What is a recursive CTE?
A recursive CTE refers to itself in its WITH definition, usually in the form "anchor + UNION ALL recursive step". It is used for hierarchical data like managers‑employees, org charts, or tree structures.
5. What is the difference between correlated and non-correlated subquery?
• Non‑correlated: runs once, independent of the outer query.
• Correlated: references columns from the outer query and runs once per outer row (e.g., SELECT ... FROM t1 WHERE col > (SELECT AVG(col) FROM t2 WHERE t2.id = t1.id)).
6. How do you remove duplicates without DISTINCT?
Use window functions:
DELETE FROM (
SELECT ROW_NUMBER() OVER (PARTITION BY col1, col2 ORDER BY id) as rn
FROM table
) t
WHERE rn > 1;
Or use GROUP BY and keep one row per group.
7. What is an INDEX and when do you use it?
An index speeds up data retrieval on specified columns (used in WHERE, JOIN, ORDER BY). Use it on columns that are frequently filtered or joined; avoid on very small tables or columns updated often.
8. Explain self-join with example.
A self‑join joins a table to itself using aliases. Example:
SELECT e1.name as employee, e2.name as manager
FROM employees e1
LEFT JOIN employees e2 ON e1.manager_id = e2.id;
Useful for parent‑child relationships.
9. What is the difference between DELETE, DROP, and TRUNCATE?
• DELETE: removes rows (can be filtered by WHERE), can be rolled back.
• TRUNCATE: removes all rows quickly, resets storage; often not logged per row.
• DROP: removes entire table (structure + data); cannot be rolled back.
10. How do you pivot/unpivot data in SQL?
• Pivot: turns rows into columns (e.g., sales per month as columns) using PIVOT or conditional aggregation (MAX(CASE WHEN ... END)).
• Unpivot: turns columns into rows (e.g., multiple month columns → one month column) using UNPIVOT or UNION ALL/VALUES.
11. What is LAG() and LEAD()?
• LAG(col, n): value of col from n rows before current row.
• LEAD(col, n): value from n rows after. Used for time‑series analysis (MoM change, prior/next values).
12. How do you handle NULL in aggregates?
Most aggregates (SUM, AVG, MAX, MIN) ignore NULL.
• COUNT(col) ignores NULL; COUNT(*) counts all rows.
• Use COALESCE() or ISNULL() to replace NULL before aggregating.
13. What is the difference between VIEW and MATERIALIZED VIEW?
• VIEW: virtual table; query runs every time you select.
• MATERIALIZED VIEW: stores result physically and refreshes periodically; faster reads, slower updates.
14. Explain ACID properties.
• Atomicity: transaction is "all or nothing".
• Consistency: valid state before and after.
• Isolation: concurrent transactions don't interfere.
• Durability: committed changes survive crashes.
15. How do you optimize a slow query?
• Add proper indexes on WHERE, JOIN, ORDER BY columns.
• Remove unnecessary SELECT *, DISTINCT, or functions on indexed columns.
• Check execution plan and avoid large scans; use LIMIT or partitioning if possible.
16. What is the difference between INNER JOIN and EXISTS?
• INNER JOIN: returns combined columns from both tables where keys match.
• EXISTS: checks if a subquery returns any rows; usually faster when you only care about existence (e.g., filtering with WHERE EXISTS). | 1 677 |
| 15 |  📊 𝗧𝗖𝗦 𝗙𝗥𝗘𝗘 𝗗𝗮𝘁𝗮 𝗔𝗻𝗮𝗹𝘆𝘁𝗶𝗰𝘀 𝗖𝗲𝗿𝘁𝗶𝗳𝗶𝗰𝗮𝘁𝗶𝗼𝗻 𝗖𝗼𝘂𝗿𝘀𝗲𝘀
Here's an amazing opportunity from TCS to learn essential data analytics skills completely FREE and earn a certificate
🔗 𝗘𝗻𝗿𝗼𝗹𝗹 𝗙𝗼𝗿 𝗙𝗥𝗘𝗘👇:
https://pdlink.in/4waJYWJ
🔥 Data Analytics continues to be one of the most in-demand career paths, and this free course is a great first step toward building job-ready skills.
⏳ Don't miss this opportunity to upskill and boost your career! | 1 780 |
| 16 | Hi Guys,
Here are some of the telegram channels which may help you in data analytics journey 👇👇
SQL: https://t.me/sqlanalyst
Power BI & Tableau: https://t.me/PowerBI_analyst
Excel: https://t.me/excel_analyst
Python: https://t.me/dsabooks
Jobs: https://t.me/datasciencej
Data Science: https://t.me/datasciencefree
Artificial intelligence: https://t.me/aiindi
Data Analysts: https://t.me/sqlspecialist
Hope it helps :) | 2 008 |
| 17 |  𝟳 𝗙𝗥𝗘𝗘 𝗖𝗲𝗿𝘁𝗶𝗳𝗶𝗰𝗮𝘁𝗶𝗼𝗻 𝗖𝗼𝘂𝗿𝘀𝗲𝘀 𝗧𝗼 𝗘𝗻𝗿𝗼𝗹𝗹 𝗜𝗻 𝟮𝟬𝟮𝟲😍
✅ 100% FREE & Beginner-Friendly
✅ Learn AI, ML, Data Science, Ethical Hacking & More
✅ Taught by Industry Experts
✅ Practical & Hands-on Learning
📢 Start learning today and take your tech career to the next level! 🚀
𝐋𝐢𝐧𝐤 👇:-
https://pdlink.in/4bQ6FpS
Enroll For FREE & Get Certified 🎓 | 2 290 |
| 18 | ⚙️ Data Analytics Roadmap
📂 Excel/Google Sheets (VLOOKUP, Pivot Tables, Charts)
∟📂 SQL (SELECT, JOINs, GROUP BY, Window Functions)
∟📂 Python/R Basics (Pandas, Data Cleaning)
∟📂 Statistics (Descriptive, Inferential, Correlation)
∟📂 Data Visualization (Tableau, Power BI, Matplotlib)
∟📂 ETL Processes (Extract, Transform, Load)
∟📂 Dashboard Design (KPIs, Storytelling)
∟📂 Business Intelligence Tools (Looker, Metabase)
∟📂 Data Quality & Governance
∟📂 A/B Testing & Experimentation
∟📂 Advanced Analytics (Cohort Analysis, Funnel Analysis)
∟📂 Big Data Basics (Spark, Airflow)
∟📂 Communication (Reports, Presentations)
∟📂 Projects (Sales Dashboard, Customer Segmentation)
∟✅ Apply for Data Analyst / BI Analyst Roles
💬 Tap ❤️ for more! | 2 147 |
| 19 |  𝗣𝗮𝘆 𝗔𝗳𝘁𝗲𝗿 𝗣𝗹𝗮𝗰𝗲𝗺𝗲𝗻𝘁 - 𝗙𝘂𝗹𝗹𝘀𝘁𝗮𝗰𝗸𝗗𝗲𝘃 𝗖𝗲𝗿𝘁𝗶𝗳𝗶𝗰𝗮𝘁𝗶𝗼𝗻 𝗪𝗶𝘁𝗵 𝗚𝗲𝗻𝗔𝗜 😍
Curriculum designed and taught by alumni from IITs & leading tech companies.
Learn Coding & Get Placed In Top Tech Companies
𝗛𝗶𝗴𝗵𝗹𝗶𝗴𝗵𝘁𝘀:-
💼 Avg. Package: ₹7.2 LPA | Highest: ₹41 LPA
𝐑𝐞𝐠𝐢𝐬𝐭𝐞𝐫 𝐍𝐨𝐰 👇:-
https://pdlink.in/42WOE5H
Hurry! Limited seats are available.🏃♂️ | 1 884 |
| 20 | ✅SQL Roadmap: Step-by-Step Guide to Master SQL 🧠💻
Whether you're aiming to be a backend dev, data analyst, or full-time SQL pro — this roadmap has got you covered 👇
📍 1. SQL Basics
⦁ SELECT, FROM, WHERE
⦁ ORDER BY, LIMIT, DISTINCT
Learn data retrieval & filtering.
📍 2. Joins Mastery
⦁ INNER JOIN, LEFT/RIGHT/FULL OUTER JOIN
⦁ SELF JOIN, CROSS JOIN
Master table relationships.
📍 3. Aggregate Functions
⦁ COUNT(), SUM(), AVG(), MIN(), MAX()
Key for reporting & analytics.
📍 4. Grouping Data
⦁ GROUP BY to group
⦁ HAVING to filter groups
Example: Sales by region, top categories.
📍 5. Subqueries & Nested Queries
⦁ Use subqueries in WHERE, FROM, SELECT
⦁ Use EXISTS, IN, ANY, ALL
Build complex logic without extra joins.
📍 6. Data Modification
⦁ INSERT INTO, UPDATE, DELETE
⦁ MERGE (advanced)
Safely change dataset content.
📍 7. Database Design Concepts
⦁ Normalization (1NF to 3NF)
⦁ Primary, Foreign, Unique Keys
Design scalable, clean DBs.
📍 8. Indexing & Query Optimization
⦁ Speed queries with indexes
⦁ Use EXPLAIN, ANALYZE to tune
Vital for big data/enterprise work.
📍 9. Stored Procedures & Functions
⦁ Reusable logic, control flow (IF, CASE, LOOP)
Backend logic inside the DB.
📍 10. Transactions & Locks
⦁ ACID properties
⦁ BEGIN, COMMIT, ROLLBACK
⦁ Lock types (SHARED, EXCLUSIVE)
Prevent data corruption in concurrency.
📍 11. Views & Triggers
⦁ CREATE VIEW for abstraction
⦁ TRIGGERS auto-run SQL on events
Automate & maintain logic.
📍 12. Backup & Restore
⦁ Backup/restore with tools (mysqldump, pg_dump)
Keep your data safe.
📍 13. NoSQL Basics (Optional)
⦁ Learn MongoDB, Redis basics
⦁ Understand where SQL ends & NoSQL begins.
📍 14. Real Projects & Practice
⦁ Build projects: Employee DB, Sales Dashboard, Blogging System
⦁ Practice on LeetCode, StrataScratch, HackerRank
📍 15. Apply for SQL Dev Roles
⦁ Tailor resume with projects & optimization skills
⦁ Prepare for interviews with SQL challenges
⦁ Know common business use cases
💡 Pro Tip: Combine SQL with Python or Excel to boost your data career options.
💬 Double Tap ♥️ For More! | 1 674 |
