Data Analyst Interview Resources
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Ko'proq ko'rsatish๐ Telegram kanali Data Analyst Interview Resources analitikasi
Data Analyst Interview Resources (@dataanalystinterview) Ingliz til segmentidagi kanali faol ishtirokchi. Hozirda hamjamiyat 52 270 obunachidan iborat bo'lib, Taสผlim toifasida 3 335-o'rinni va Hindiston mintaqasida 7 194-o'rinni egallagan.
๐ Auditoriya koโrsatkichlari va dinamika
ะฝะตะฒัะดะพะผะพ sanasidan buyon loyiha tez oโsib, 52 270 obunachiga ega boโldi.
10 Iyun, 2026 dagi oxirgi maโlumotlarga koโra kanal barqaror faollikka ega. Oxirgi 30 kunda obunachilar soni 235 ga, soโnggi 24 soatda esa 24 ga oโzgardi va umumiy qamrov yuqori darajada qolmoqda.
- Tasdiqlash holati: Tasdiqlanmagan
- Jalb etish (ER): Auditoriya oโrtacha 2.43% darajada jalb etiladi. Nashrdan keyingi dastlabki 24 soatda kontent odatda umumiy obunachilar sonining 0.90% ini tashkil etuvchi reaksiyalarni toโplaydi.
- Post qamrovi: Har bir post oโrtacha 1 272 marta koโriladi; birinchi sutkada odatda 471 ta koโrish yigโiladi.
- Reaksiyalar va oโzaro taโsir: Auditoriya faol: har bir postga oโrtacha 3 ta reaksiya keladi.
- Tematik yoโnalishlar: Kontent sql, row, |--, dataset, visualization kabi asosiy mavzularga jamlangan.
๐ Tavsif va kontent siyosati
Muallif resursni shaxsiy fikrni ifoda etish maydoni sifatida taโriflaydi:
โJoin our telegram channel to learn how data analysis can reveal fascinating patterns, trends, and stories hidden within the numbers! ๐
For ads & suggestions: @love_dataโ
Yuqori yangilanish chastotasi (oxirgi maโlumot 11 Iyun, 2026 da olingan) sababli kanal doimo dolzarb va katta qamrovli boโlib qoladi. Analitika auditoriya kontent bilan faol hamkorlik qilishini, uni Taสผlim toifasidagi muhim taโsir nuqtasiga aylantirishini koโrsatadi.
CALCULATE(SUM(Sales[Amount]), Region = "West")
2๏ธโฃ What is ALL() function in DAX?
Removes filters โ useful for calculating totals regardless of filters.
3๏ธโฃ How does FILTER() differ from CALCULATE()?
FILTER returns a table; CALCULATE modifies context using that table.
4๏ธโฃ Difference between SUMX and SUM?
SUMX iterates over rows, applying an expression; SUM just totals a column.
5๏ธโฃ Explain STAR vs SNOWFLAKE Schema
- Star: denormalized, simple
- Snowflake: normalized, complex relationships
6๏ธโฃ What is a Composite Model?
Allows combining Import + DirectQuery sources in one report.
7๏ธโฃ What are Virtual Tables in DAX?
Tables created in memory during calculation โ not physical.
8๏ธโฃ What is the difference between USERNAME() and USERPRINCIPALNAME()?
Used for dynamic RLS.
- USERNAME(): Local machine login
- USERPRINCIPALNAME(): Cloud identity (email)
9๏ธโฃ Explain Time Intelligence Functions
Examples:
- TOTALYTD(), DATESINPERIOD(), SAMEPERIODLASTYEAR()
Used for date-based calculations.
๐ Common DAX Optimization Tips
- Avoid complex nested functions
- Use variables (VAR)
- Reduce row context with calculated columns
1๏ธโฃ1๏ธโฃ What is Incremental Refresh?
Only refreshes new/changed data โ improves performance in large datasets.
1๏ธโฃ2๏ธโฃ What are Parameters in Power BI?
User-defined inputs to make reports dynamic and reusable.
1๏ธโฃ3๏ธโฃ What is a Dataflow?
Reusable ETL layer in Power BI Service using Power Query Online.
1๏ธโฃ4๏ธโฃ Difference Between Live Connection vs DirectQuery vs Import
- Import: Fast, offline
- DirectQuery: Real-time, slower
- Live Connection: Full model lives on SSAS
1๏ธโฃ5๏ธโฃ Advanced Visuals Use Cases
- Decomposition Tree for root cause analysis
- KPI Cards for performance metrics
- Paginated Reports for printable tables
๐ Tap for more!WHERE filters rows before grouping (used with SELECT, UPDATE).
โฆ 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:
โฆ INNER JOIN: returns matching rows from both tables.
โฆ LEFT JOIN (LEFT OUTER JOIN): all rows from the left table, matched rows from right.
โฆ RIGHT JOIN (RIGHT OUTER JOIN): all rows from right table, matched rows from left.
โฆ FULL JOIN (FULL OUTER JOIN): all rows when thereโs a match in either table.
โฆ CROSS JOIN: Cartesian product of both tables.
7. How do you optimize slow-performing SQL queries?
โฆ Use indexes appropriately to speed up lookups.
โฆ Avoid SELECT *; only select necessary columns.
โฆ Use joins carefully; filter early with WHERE clauses.
โฆ Analyze execution plans to identify bottlenecks.
โฆ Avoid unnecessary subqueries; use EXISTS or JOINs.
โฆ Limit result sets with pagination if dealing with large datasets.
8. What is a primary key? What is a foreign key?
โฆ Primary Key: A unique identifier for records in a table; it cannot be NULL.
โฆ 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.
โฆ Indexes speed up data retrieval by providing quick lookups.
โฆ Clustered Index: Sorts and stores the actual data rows in the table based on the key; a table can have only one clustered index.
โฆ 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 โฅ๏ธ for Part 2
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