Data Analytics
Perfect channel to learn Data Analytics Learn SQL, Python, Alteryx, Tableau, Power BI and many more For Promotions: @coderfun @love_data
Показати більше📈 Аналітичний огляд Telegram-каналу Data Analytics
Канал Data Analytics (@sqlspecialist) у мовному сегменті Англійська є активним учасником. На даний момент спільнота об'єднує 109 620 підписників, посідаючи 1 126 місце в категорії Технології та додатки та 2 380 місце у регіоні Індія.
📊 Показники аудиторії та динаміка
З моменту свого створення невідомо, проект продемонстрував стрімке зростання, зібравши аудиторію у 109 620 підписників.
За останніми даними від 18 червня, 2026, канал демонструє стабільну активність. Хоча за останні 30 днів спостерігається зміна кількості учасників на 686, а за останні 24 години на -13, загальне охоплення залишається високим.
- Статус верифікації: Не верифікований
- Рівень залученості (ER): Середній показник залученості аудиторії становить 3.27%. Протягом перших 24 годин після публікації контент зазвичай збирає 1.44% реакцій від загальної кількості підписників.
- Охоплення публікацій: В середньому кожен допис отримує 3 581 переглядів. Протягом першої доби публікація в середньому набирає 1 584 переглядів.
- Реакції та взаємодія: Аудиторія активно підтримує контент: середня кількість реакцій на один пост – 8.
- Тематичні інтереси: Контент зосереджений навколо ключових тем, таких як row, sql, analytic, analyst, visualization.
📝 Опис та контентна політика
Автор описує ресурс як майданчик для висловлення суб'єктивної думки:
“Perfect channel to learn Data Analytics
Learn SQL, Python, Alteryx, Tableau, Power BI and many more
For Promotions: @coderfun @love_data”
Завдяки високій частоті оновлень (останні дані отримано 19 червня, 2026), канал підтримує актуальність та високий рівень охоплення публікацій. Аналітика показує, що аудиторія активно взаємодіє з контентом, що робить його важливою точкою впливу в категорії Технології та додатки.
SELECT MAX(salary) AS second_highest_salary
FROM employees
WHERE salary < (SELECT MAX(salary) FROM employees);
⭐ Using Window FunctionSELECT salary
FROM (
SELECT salary, DENSE_RANK() OVER (ORDER BY salary DESC) AS rnk
FROM employees
) t
WHERE rnk = 2;
✅ 17. Explain INNER JOIN vs LEFT JOIN vs FULL JOIN with examples for employees and departments.
⭐ INNER JOIN → Only matching recordsSELECT e.name, d.department_name
FROM employees e
INNER JOIN departments d ON e.department_id = d.id;
⭐ LEFT JOIN → All employees + matching departmentsSELECT e.name, d.department_name
FROM employees e
LEFT JOIN departments d ON e.department_id = d.id;
⭐ FULL JOIN → All records from both tablesSELECT e.name, d.department_name
FROM employees e
FULL JOIN departments d ON e.department_id = d.id;
✅ 18. Find and remove duplicate records using CTE + ROW_NUMBER().
⭐ Find DuplicatesWITH cte AS (
SELECT *, ROW_NUMBER() OVER(PARTITION BY email ORDER BY id) rn
FROM employees
)
SELECT * FROM cte WHERE rn > 1;
⭐ Remove DuplicatesWITH cte AS (
SELECT *, ROW_NUMBER() OVER(PARTITION BY email ORDER BY id) rn
FROM employees
)
DELETE FROM cte WHERE rn > 1;
✅ 19. Explain WHERE vs HAVING with GROUP BY. Show department-wise avg salary > 50k.
👉 Difference
WHERE → filter before grouping
HAVING → filter after groupingSELECT department_id, AVG(salary) AS avg_salary
FROM employees
GROUP BY department_id
HAVING AVG(salary) > 50000;
✅ 20. Explain RANK vs DENSE_RANK vs ROW_NUMBER partitioned by department ordered by salary.SELECT name, department_id, salary,
ROW_NUMBER() OVER(PARTITION BY department_id ORDER BY salary DESC) rn,
RANK() OVER(PARTITION BY department_id ORDER BY salary DESC) rnk,
DENSE_RANK() OVER(PARTITION BY department_id ORDER BY salary DESC) drnk
FROM employees;
✅ 21. Find top 5 products by total sales using GROUP BY + LIMIT.SELECT product_id, SUM(sales_amount) AS total_sales
FROM sales
GROUP BY product_id
ORDER BY total_sales DESC
LIMIT 5;
✅ 22. Write a self join to show employee name and manager name.SELECT e.name AS employee, m.name AS manager
FROM employees e
LEFT JOIN employees m ON e.manager_id = m.employee_id;
✅ 23. Handle NULL salaries using COALESCE, IS NULL, IFNULL.
⭐ Using COALESCESELECT name, COALESCE(salary, 0) AS salary
FROM employees;
⭐ Using IS NULLSELECT * FROM employees WHERE salary IS NULL;
✅ 24. Pivot sales data by month using CASE statement.SELECT
SUM(CASE WHEN month = 'Jan' THEN sales ELSE 0 END) AS Jan,
SUM(CASE WHEN month = 'Feb' THEN sales ELSE 0 END) AS Feb,
SUM(CASE WHEN month = 'Mar' THEN sales ELSE 0 END) AS Mar
FROM sales;
✅ 25. Subquery vs JOIN — which is faster? Why?
JOIN is usually faster, subquery is easier to read.
✅ 26. Write a recursive CTE for company hierarchy (CEO → managers → employees).WITH RECURSIVE emp_hierarchy AS (
SELECT employee_id, name, manager_id
FROM employees
WHERE manager_id IS NULL
UNION ALL
SELECT e.employee_id, e.name, e.manager_id
FROM employees e
JOIN emp_hierarchy h ON e.manager_id = h.employee_id
)
SELECT * FROM emp_hierarchy;
✅ 27. Explain clustered vs non-clustered indexes. When to use each?
⭐ Clustered Index: physically sorts table data
⭐ Non-Clustered Index: separate structure pointing to data
SQL Resources: https://whatsapp.com/channel/0029VanC5rODzgT6TiTGoa1v
Double Tap ♥️ For More=TRIM(A1)
- CLEAN() → removes non-printable characters =CLEAN(A1)
- Remove Duplicates → Data → Remove Duplicates
- Text to Columns → split data
- Find & Replace (Ctrl+H) → fix values
- Filter → remove blanks or errors
2️⃣ Absolute vs Relative References
Relative (A1) → changes when copied
Absolute ($A$1) → stays fixed
When to use:
- Relative → normal calculations
- Absolute → fixed values (tax rate, constants)
3️⃣ Create PivotTable for Sales Analysis
Steps:
1. Select data
2. Insert → PivotTable
3. Drag: Region → Rows, Product → Columns, Sales → Values
Used for fast data summarization.
4️⃣ VLOOKUP Formula + #N/A Fix
Formula: =VLOOKUP(A2, Sheet2!A:B, 2, FALSE)
Fix #N/A:
- Check lookup value exists
- Match data types
Use: =IFERROR(VLOOKUP(A2, A:B, 2, FALSE),"Not Found")
5️⃣ INDEX-MATCH vs VLOOKUP
VLOOKUP: =VLOOKUP(A2,A:B,2,FALSE)
INDEX-MATCH: =INDEX(B:B, MATCH(A2,A:A,0))
✅ Why INDEX-MATCH?
- Faster for large data
- Works left lookup
- More flexible
6️⃣ COUNTIF vs SUMIF vs COUNTIFS
COUNTIF → count condition =COUNTIF(A:A,"East")
SUMIF → sum condition =SUMIF(A:A,"East",B:B)
COUNTIFS → multiple conditions =COUNTIFS(A:A,"East",B:B,">500")
7️⃣ Goal Seek
Used for what-if analysis.
Steps:
1. Data → What-if Analysis → Goal Seek
2. Set cell → target value
3. Change variable cell
Example: target revenue calculation.
8️⃣ Conditional Formatting Top 10%
Steps: Select data
Home → Conditional Formatting
Top/Bottom Rules → Top 10%
9️⃣ Dynamic Dashboard + Slicers
Create PivotTable
Insert → Slicer
Insert → Timeline (for dates)
Connect slicers to multiple visuals
Used for interactive dashboards.
🔟 SUMPRODUCT (Multi-condition sum)
=SUMPRODUCT((A2:A10="East")(B2:B10>500)C2:C10)
Used for weighted or multiple-condition calculations.
1️⃣1️⃣ What is Power Query?
Excel’s ETL tool.
Steps:
- Get Data → Load data
- Remove columns
- Change types
- Remove duplicates
- Load cleaned data
Used for automation and transformation.
1️⃣2️⃣ Freeze Panes vs Split Panes
Freeze Panes → lock rows/columns while scrolling
Split Panes → divide screen into sections
1️⃣3️⃣ XLOOKUP vs VLOOKUP
XLOOKUP: =XLOOKUP(A2,A:A,B:B)
✅ Advantages:
- Left lookup
- No column index
- Default exact match
- Handles errors
1️⃣4️⃣ Circular References Fix
Occurs when formula refers to itself.
Fix:
Formulas → Error Checking → Circular References
Correct formula logic
1️⃣5️⃣ Data Validation + Named Range
Steps:
1. Formulas → Define Name
2. Data → Data Validation → List
3. Select named range
Used for dropdown lists.
Excel Resources: https://whatsapp.com/channel/0029VaifY548qIzv0u1AHz3i
Double Tap ♥️ For MoreSELECT DISTINCT column_name
FROM employees;
👉 Returns unique records but does not delete duplicates.
✅ 2️⃣ Using GROUP BY (to identify duplicates)
SELECT name, COUNT(*)
FROM employees
GROUP BY name
HAVING COUNT(*) > 1;
👉 Helps find duplicate records.
✅ 3️⃣ Delete Duplicates Using ROW_NUMBER() (Most Important ⭐)
(Keeps one record and deletes others)
DELETE FROM employees
WHERE id IN (
SELECT id FROM (
SELECT id,
ROW_NUMBER() OVER (
PARTITION BY name, salary
ORDER BY id
) AS rn
FROM employees
) t
WHERE rn > 1
);
🧠 Logic Breakdown:
- DISTINCT → shows unique records
- GROUP BY → identifies duplicates
- ROW_NUMBER() → removes duplicates safely
✅ Use Case: Data cleaning, ETL processes, data quality checks.
💡 Tip: Always take a backup before deleting duplicate records.
💬 Tap ❤️ for more!SELECT department_id, AVG(salary) AS avg_salary
FROM employees
GROUP BY department_id
HAVING AVG(salary) > 70000;
🔎 Q2. Count employees in each department having more than 5 employees.
🗂️ Table: "employees(emp_id, name, department_id)"
✅ Answer:
SELECT department_id, COUNT(*) AS total_employees
FROM employees
GROUP BY department_id
HAVING COUNT(*) > 5;
🔎 Q3. Find the department with the highest total salary.
🗂️ Table: "employees(emp_id, department_id, salary)"
✅ Answer:
SELECT department_id
FROM employees
GROUP BY department_id
ORDER BY SUM(salary) DESC
LIMIT 1;
🔎 Q4. Get departments where the minimum salary is greater than 30,000.
🗂️ Table: "employees(emp_id, department_id, salary)"
✅ Answer:
SELECT department_id, MIN(salary) AS min_salary
FROM employees
GROUP BY department_id
HAVING MIN(salary) > 30000;
🔎 Q5. Find the difference between highest and lowest salary in each department.
🗂️ Table: "employees(emp_id, department_id, salary)"
✅ Answer:
SELECT department_id, MAX(salary) - MIN(salary) AS salary_difference
FROM employees
GROUP BY department_id;
Double Tap ♥️ For More
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