Data Analyst Interview Resources
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Channel Data Analyst Interview Resources (@dataanalystinterview) in the English language segment is an active participant. Currently, the community unites 52 270 subscribers, ranking 3 335 in the Education category and 7 194 in the India region.
๐ Audience metrics and dynamics
Since its creation on ะฝะตะฒัะดะพะผะพ, the project has demonstrated rapid growth, gathering an audience of 52 270 subscribers.
According to the latest data from 10 June, 2026, the channel demonstrates stable activity. Although there has been a change in the number of participants by 235 over the last 30 days and by 24 over the last 24 hours, overall reach remains high.
- Verification status: Not verified
- Engagement rate (ER): The average audience engagement rate is 2.43%. Within the first 24 hours after publication, content typically collects 0.90% reactions from the total number of subscribers.
- Post reach: On average, each post receives 1 272 views. Within the first day, a publication typically gains 471 views.
- Reactions and interaction: The audience actively supports content: the average number of reactions per post is 3.
- Thematic interests: Content is focused on key topics such as sql, row, |--, dataset, visualization.
๐ Description and content policy
The author describes the resource as a platform for expressing subjective opinions:
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
Thanks to the high frequency of updates (latest data received on 11 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 Education category.
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;
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