Data Analyst Interview Resources
Join our telegram channel to learn how data analysis can reveal fascinating patterns, trends, and stories hidden within the numbers! 📊 For ads & suggestions: @love_data
Ko'proq ko'rsatish📈 Telegram kanali Data Analyst Interview Resources analitikasi
Data Analyst Interview Resources (@dataanalystinterview) Ingliz til segmentidagi kanali faol ishtirokchi. Hozirda hamjamiyat 52 614 obunachidan iborat bo'lib, Taʼlim toifasida 3 245-o'rinni va Hindiston mintaqasida 6 767-o'rinni egallagan.
📊 Auditoriya ko‘rsatkichlari va dinamika
невідомо sanasidan buyon loyiha tez o‘sib, 52 614 obunachiga ega bo‘ldi.
27 Avgust, 2026 dagi oxirgi ma’lumotlarga ko‘ra kanal barqaror faollikka ega. Oxirgi 30 kunda obunachilar soni 60 ga, so‘nggi 24 soatda esa -8 ga o‘zgardi va umumiy qamrov yuqori darajada qolmoqda.
- Tasdiqlash holati: Tasdiqlanmagan
- Jalb etish (ER): Auditoriya o‘rtacha 1.93% darajada jalb etiladi. Nashrdan keyingi dastlabki 24 soatda kontent odatda umumiy obunachilar sonining 0.83% ini tashkil etuvchi reaksiyalarni to‘playdi.
- Post qamrovi: Har bir post o‘rtacha 1 018 marta ko‘riladi; birinchi sutkada odatda 438 ta ko‘rish yig‘iladi.
- Reaksiyalar va o‘zaro ta’sir: Auditoriya faol: har bir postga o‘rtacha 2 ta reaksiya keladi.
- Tematik yo‘nalishlar: Kontent sql, row, |--, dataset, visualization kabi asosiy mavzularga jamlangan.
📝 Tavsif va kontent siyosati
Muallif resursni shaxsiy fikrni ifoda etish maydoni sifatida ta’riflaydi:
“Join our telegram channel to learn how data analysis can reveal fascinating patterns, trends, and stories hidden within the numbers! 📊
For ads & suggestions: @love_data”
Yuqori yangilanish chastotasi (oxirgi ma’lumot 28 Avgust, 2026 da olingan) sababli kanal doimo dolzarb va katta qamrovli bo‘lib qoladi. Analitika auditoriya kontent bilan faol hamkorlik qilishini, uni Taʼlim toifasidagi muhim ta’sir nuqtasiga aylantirishini ko‘rsatadi.
CALCULATE(SUM(Sales[Amount]), Region = "West")
2️⃣ What is ALL() function in DAX?
Removes filters — useful for calculating totals regardless of filters.
3️⃣ How does FILTER() differ from CALCULATE()?
FILTER returns a table; CALCULATE modifies context using that table.
4️⃣ Difference between SUMX and SUM?
SUMX iterates over rows, applying an expression; SUM just totals a column.
5️⃣ Explain STAR vs SNOWFLAKE Schema
- Star: denormalized, simple
- Snowflake: normalized, complex relationships
6️⃣ What is a Composite Model?
Allows combining Import + DirectQuery sources in one report.
7️⃣ What are Virtual Tables in DAX?
Tables created in memory during calculation — not physical.
8️⃣ What is the difference between USERNAME() and USERPRINCIPALNAME()?
Used for dynamic RLS.
- USERNAME(): Local machine login
- USERPRINCIPALNAME(): Cloud identity (email)
9️⃣ Explain Time Intelligence Functions
Examples:
- TOTALYTD(), DATESINPERIOD(), SAMEPERIODLASTYEAR()
Used for date-based calculations.
🔟 Common DAX Optimization Tips
- Avoid complex nested functions
- Use variables (VAR)
- Reduce row context with calculated columns
1️⃣1️⃣ What is Incremental Refresh?
Only refreshes new/changed data – improves performance in large datasets.
1️⃣2️⃣ What are Parameters in Power BI?
User-defined inputs to make reports dynamic and reusable.
1️⃣3️⃣ What is a Dataflow?
Reusable ETL layer in Power BI Service using Power Query Online.
1️⃣4️⃣ Difference Between Live Connection vs DirectQuery vs Import
- Import: Fast, offline
- DirectQuery: Real-time, slower
- Live Connection: Full model lives on SSAS
1️⃣5️⃣ Advanced Visuals Use Cases
- Decomposition Tree for root cause analysis
- KPI Cards for performance metrics
- Paginated Reports for printable tables
👍 Tap for more!WHERE filters rows before grouping (used with SELECT, UPDATE).
⦁ HAVING filters groups after aggregation (used with GROUP BY), e.g., filtering aggregated results like sums or counts.
5. Write a SQL query to find the second highest salary in a table.
Using a subquery:
SELECT MAX(salary) FROM employees
WHERE salary < (SELECT MAX(salary) FROM employees);
Or using DENSE_RANK():
SELECT salary FROM (
SELECT salary, DENSE_RANK() OVER (ORDER BY salary DESC) as rnk
FROM employees) t
WHERE rnk = 2;
6. What is a JOIN? Explain different types of JOINs.
A JOIN combines rows from two or more tables based on a related column:
⦁ INNER JOIN: returns matching rows from both tables.
⦁ LEFT JOIN (LEFT OUTER JOIN): all rows from the left table, matched rows from right.
⦁ RIGHT JOIN (RIGHT OUTER JOIN): all rows from right table, matched rows from left.
⦁ FULL JOIN (FULL OUTER JOIN): all rows when there’s a match in either table.
⦁ CROSS JOIN: Cartesian product of both tables.
7. How do you optimize slow-performing SQL queries?
⦁ Use indexes appropriately to speed up lookups.
⦁ Avoid SELECT *; only select necessary columns.
⦁ Use joins carefully; filter early with WHERE clauses.
⦁ Analyze execution plans to identify bottlenecks.
⦁ Avoid unnecessary subqueries; use EXISTS or JOINs.
⦁ Limit result sets with pagination if dealing with large datasets.
8. What is a primary key? What is a foreign key?
⦁ Primary Key: A unique identifier for records in a table; it cannot be NULL.
⦁ Foreign Key: A field that creates a link between two tables by referring to the primary key in another table, enforcing referential integrity.
9. What are indexes? Explain clustered and non-clustered indexes.
⦁ Indexes speed up data retrieval by providing quick lookups.
⦁ Clustered Index: Sorts and stores the actual data rows in the table based on the key; a table can have only one clustered index.
⦁ Non-Clustered Index: Creates a separate structure that points to the data rows; tables can have multiple non-clustered indexes.
10. Write a SQL query to fetch the top 5 records from a table.
In SQL Server and PostgreSQL:
SELECT * FROM table_name
ORDER BY some_column DESC
LIMIT 5;
In SQL Server (older syntax):
SELECT TOP 5 * FROM table_name
ORDER BY some_column DESC;
React ♥️ for Part 2