Data Analytics
Perfect channel to learn Data Analytics Learn SQL, Python, Alteryx, Tableau, Power BI and many more For Promotions: @coderfun @love_data
Show more📈 Analytical overview of Telegram channel Data Analytics
Channel Data Analytics (@sqlspecialist) in the English language segment is an active participant. Currently, the community unites 109 605 subscribers, ranking 1 124 in the Technologies & Applications category and 2 373 in the India region.
📊 Audience metrics and dynamics
Since its creation on невідомо, the project has demonstrated rapid growth, gathering an audience of 109 605 subscribers.
According to the latest data from 19 June, 2026, the channel demonstrates stable activity. Although there has been a change in the number of participants by 624 over the last 30 days and by -15 over the last 24 hours, overall reach remains high.
- Verification status: Not verified
- Engagement rate (ER): The average audience engagement rate is 3.26%. Within the first 24 hours after publication, content typically collects 1.27% reactions from the total number of subscribers.
- Post reach: On average, each post receives 3 575 views. Within the first day, a publication typically gains 1 388 views.
- Reactions and interaction: The audience actively supports content: the average number of reactions per post is 9.
- Thematic interests: Content is focused on key topics such as row, sql, analytic, analyst, visualization.
📝 Description and content policy
The author describes the resource as a platform for expressing subjective opinions:
“Perfect channel to learn Data Analytics
Learn SQL, Python, Alteryx, Tableau, Power BI and many more
For Promotions: @coderfun @love_data”
Thanks to the high frequency of updates (latest data received on 20 June, 2026), the channel maintains relevance and a high level of publication reach. Analytics show that the audience actively interacts with content, making it an important point of influence in the Technologies & Applications category.
SELECT department, COUNT(*)
FROM employees
WHERE salary > 50000
GROUP BY department
HAVING COUNT(*) > 5
ORDER BY COUNT(*) DESC
LIMIT 10;
💡 Note: Even though SELECT comes first when we write SQL, it's processed after WHERE, GROUP BY, and HAVING—knowing this prevents sneaky bugs!
💬 Tap ❤️ if this helped clarify things!import numpy as np
def remove_outliers(data):
q1 = np.percentile(data, 25)
q3 = np.percentile(data, 75)
iqr = q3 - q1
lower = q1 - 1.5 * iqr
upper = q3 + 1.5 * iqr
return [x for x in data if lower <= x <= upper]
2️⃣ Convert a nested list to a flat list.
nested = [[1, 2], [3, 4],]
flat = [item for sublist in nested for item in sublist]
3️⃣ Read a CSV file and count rows with nulls.
import pandas as pd
df = pd.read_csv('data.csv')
null_rows = df.isnull().any(axis=1).sum()
print("Rows with nulls:", null_rows)
4️⃣ How do you handle missing data in pandas?
⦁ Drop missing rows: df.dropna()
⦁ Fill missing values: df.fillna(value)
⦁ Check missing data: df.isnull().sum()
5️⃣ Explain the difference between loc[] and iloc[].
⦁ loc[]: Label-based indexing (e.g., row/column names)
Example: df.loc[0, 'Name']
⦁ iloc[]: Position-based indexing (e.g., row/column numbers)
Example: df.iloc
💬 Tap ❤️ for more!SELECT MAX(salary)
FROM employee
WHERE salary < (SELECT MAX(salary) FROM employee);
2️⃣ Get the top 3 products by revenue from sales table.
SELECT product_id, SUM(revenue) AS total_revenue
FROM sales
GROUP BY product_id
ORDER BY total_revenue DESC
LIMIT 3;
3️⃣ Use JOIN to combine customer and order data.
SELECT c.customer_name, o.order_id, o.order_date
FROM customers c
JOIN orders o ON c.customer_id = o.customer_id;
(That's an INNER JOIN—use LEFT JOIN to include all customers, even without orders.)
4️⃣ Difference between WHERE and HAVING?
⦁ WHERE filters rows before aggregation (e.g., on individual records).
⦁ HAVING filters rows after aggregation (used with GROUP BY on aggregates).
Example:
SELECT department, COUNT(*)
FROM employee
GROUP BY department
HAVING COUNT(*) > 5;
5️⃣ Explain INDEX and how it improves performance.
An INDEX is a data structure that improves the speed of data retrieval.
It works like a lookup table and reduces the need to scan every row in a table.
Especially useful for large datasets and on columns used in WHERE, JOIN, or ORDER BY—think 10x faster queries, but it slows inserts/updates a bit.
💬 Tap ❤️ for more!SELECT MAX(salary)
FROM employee
WHERE salary < (SELECT MAX(salary) FROM employee);
2️⃣ Get the top 3 products by revenue from sales table.
SELECT product_id, SUM(revenue) AS total_revenue
FROM sales
GROUP BY product_id
ORDER BY total_revenue DESC
LIMIT 3;
3️⃣ Use JOIN to combine customer and order data.
SELECT c.customer_name, o.order_id, o.order_date
FROM customers c
JOIN orders o ON c.customer_id = o.customer_id;
(That's an INNER JOIN—use LEFT JOIN to include all customers, even without orders.)
4️⃣ Difference between WHERE and HAVING?
⦁ WHERE filters rows before aggregation (e.g., on individual records).
⦁ HAVING filters rows after aggregation (used with GROUP BY on aggregates).
Example:
SELECT department, COUNT(*)
FROM employee
GROUP BY department
HAVING COUNT(*) > 5;
5️⃣ Explain INDEX and how it improves performance.
An INDEX is a data structure that improves the speed of data retrieval.
It works like a lookup table and reduces the need to scan every row in a table.
Especially useful for large datasets and on columns used in WHERE, JOIN, or ORDER BY—think 10x faster queries, but it slows inserts/updates a bit.
💬 Tap ❤️ for more!import sqlite3
conn = sqlite3.connect('data.db')
cursor = conn.cursor()
3️⃣0️⃣ What is the difference between.loc and.iloc in Pandas?
⦁ .loc[] is label-based indexing (e.g., df.loc by row label)
⦁ .iloc[] is position-based indexing (e.g., df.iloc by row number)
💬 Tap ❤️ for Part 5SELECT MAX(salary)
FROM employees
WHERE salary < (SELECT MAX(salary) FROM employees);
6️⃣ What is the difference between INNER JOIN and LEFT JOIN?
⦁ INNER JOIN: Returns only matching rows from both tables.
⦁ LEFT JOIN: Returns all rows from the left table, and matching rows from the right (NULLs if no match).
7️⃣ What are outliers? How do you detect and handle them?
Outliers are values that deviate significantly from the rest of the data.
Detection Methods:
⦁ IQR (Interquartile Range)
⦁ Z-score
Handling Methods:
⦁ Remove outliers
⦁ Cap values
⦁ Use transformation (e.g., log scale)
8️⃣ What is a Pivot Table?
A pivot table is a data summarization tool that allows quick grouping, aggregation, and analysis of data in spreadsheets or BI tools. It's useful for analyzing patterns and trends.
9️⃣ How do you validate a data model?
⦁ Split data into training and testing sets
⦁ Use cross-validation (e.g., k-fold)
⦁ Evaluate metrics like Accuracy, Precision, Recall, F1-Score, RMSE, etc.
🔟 What is Hypothesis Testing? Difference between t-test and z-test?
Hypothesis testing is a statistical method to test assumptions about a population.
⦁ T-test: Used when sample size is small and population variance is unknown.
⦁ Z-test: Used when sample size is large or population variance is known.
💬 Tap ❤️ for Part 2!
Available now! Telegram Research 2025 — the year's key insights 
