Zomato Most Asked SQL Interview Questions Experience : CTC - 25LPA
1/ How would you analyze a dataset with missing values?
2/ Can you explain the difference between inner join and left join in SQL?
3/ How do you approach data cleaning in a dataset?
4/ What is the difference between UNION and UNION ALL in SQL?
5/ How would you calculate the mean, median, and mode for a given dataset?
6/ Explain a time when you used data visualization to communicate insights effectively.
7/ How do you handle outliers in a dataset?
8/ Describe the differences between supervised and unsupervised learning.
9/ What is A/B testing, and how would you set it up in a real-world scenario?
10/ How would you approach building a recommendation system?
11/ Explain the concept of time series analysis and its applications.
12/ What is normalization in databases, and why is it important?
13/ How do you decide on the appropriate statistical test for a given dataset?
14/ How would you calculate and interpret correlation between two variables?
15/ What is the difference between a primary key and a foreign key in a relational database?
16/ Can you explain the concept of pivot tables in Excel?
17/ Describe a scenario where you had to clean and merge large datasets. How did you approach it?
18/ How would you determine if a dataset is biased?
19/ What methods would you use to assess the quality of a dataset?
20/ How would you use SQL to find the top 10 highest-grossing products in a sales database?
These questions cover a variety of advanced SQL concepts such as window functions, self-joins, aggregations, string operations, date/time handling, and recursive queries.
Remember these questions are just a part to help you for a quick revision.
But if you are aiming for top companies, you need indepth preparation of these topics. Only touching the surface won't help you.
1/ How would you analyze a dataset with missing values?
2/ Can you explain the difference between inner join and left join in SQL?
3/ How do you approach data cleaning in a dataset?
4/ What is the difference between UNION and UNION ALL in SQL?
5/ How would you calculate the mean, median, and mode for a given dataset?
6/ Explain a time when you used data visualization to communicate insights effectively.
7/ How do you handle outliers in a dataset?
8/ Describe the differences between supervised and unsupervised learning.
9/ What is A/B testing, and how would you set it up in a real-world scenario?
10/ How would you approach building a recommendation system?
11/ Explain the concept of time series analysis and its applications.
12/ What is normalization in databases, and why is it important?
13/ How do you decide on the appropriate statistical test for a given dataset?
14/ How would you calculate and interpret correlation between two variables?
15/ What is the difference between a primary key and a foreign key in a relational database?
16/ Can you explain the concept of pivot tables in Excel?
17/ Describe a scenario where you had to clean and merge large datasets. How did you approach it?
18/ How would you determine if a dataset is biased?
19/ What methods would you use to assess the quality of a dataset?
20/ How would you use SQL to find the top 10 highest-grossing products in a sales database?
These questions cover a variety of advanced SQL concepts such as window functions, self-joins, aggregations, string operations, date/time handling, and recursive queries.
Remember these questions are just a part to help you for a quick revision.
But if you are aiming for top companies, you need indepth preparation of these topics. Only touching the surface won't help you.
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16 Power BI Interview Questions with Answers for you
1. How do you improve the performance of a Power BI report?
Optimize data models, use aggregations, limit visuals on a report page, apply filters to reduce data load, and enable query folding.
2. What type of data sources did you use in your previous project?
Depending on the project requirements, common sources include SQL Server, Azure, Excel, and APIs.
3. What is the difference between Star Schema and Snowflake Schema?
A Star Schema has a central fact table connected to dimension tables, while Snowflake Schema normalizes dimension tables into sub-tables.
4. What is the CALCULATED function in Power BI?
CALCULATED modifies the context of a calculation and returns the result based on the new filters.
5. Tell me about complex DAX functions you used.
I have used functions like CALCULATE, FILTER, and RANKX to create complex calculations for performance metrics.
6. How do you install the Data Gateway in Power BI?
Download the Gateway from Power BI service, install it, and configure it with the on-premises data source.
7. What is the difference between Data Query and Data Flow?
Data Query refers to queries in Power Query Editor, while Data Flow is used to transform and reuse data in multiple datasets.
8. What is the difference between Calculated Columns and Measures?
Calculated columns are static and stored in the model, while measures are dynamic and calculated during report interaction.
9. What is Query Folding in Power BI?
A: Query folding optimizes queries by delegating transformations back to the data source to improve performance.
10. What is the difference between RANK and DENSE RANK in SQL?
A: RANK skips numbers for ties, whereas DENSE RANK assigns consecutive ranks even with ties.
11. What are the types of Context in Power BI?
There are three types: Row Context, Filter Context, and Query Context, used to manage how data is filtered and displayed.
12. Give an example of INNER JOIN in SQL.
SELECT * FROM Orders o INNER JOIN Customers c ON o.CustomerID = c.CustomerID;
returns rows where the condition is met.
13. What is the difference between Filter and Slicer in Power BI?
Filters are applied in the backend, while slicers are visual controls for users to filter data interactively on the report.
14. What are the fundamentals of Power BI?
Power BI fundamentals include data modeling, DAX calculations, data visualization, and report sharing through the Power BI Service.
15. What is Row Level Security in Power BI?
It defines rules to control which data users can view in Power BI reports, based on their roles.
16. What are the different types of subscriptions in Power BI Report Server?
Subscriptions include email-based report delivery, SharePoint delivery, and Power BI Service for scheduled data refresh.
Like this post if you need more content like this 👍❤️
1. How do you improve the performance of a Power BI report?
Optimize data models, use aggregations, limit visuals on a report page, apply filters to reduce data load, and enable query folding.
2. What type of data sources did you use in your previous project?
Depending on the project requirements, common sources include SQL Server, Azure, Excel, and APIs.
3. What is the difference between Star Schema and Snowflake Schema?
A Star Schema has a central fact table connected to dimension tables, while Snowflake Schema normalizes dimension tables into sub-tables.
4. What is the CALCULATED function in Power BI?
CALCULATED modifies the context of a calculation and returns the result based on the new filters.
5. Tell me about complex DAX functions you used.
I have used functions like CALCULATE, FILTER, and RANKX to create complex calculations for performance metrics.
6. How do you install the Data Gateway in Power BI?
Download the Gateway from Power BI service, install it, and configure it with the on-premises data source.
7. What is the difference between Data Query and Data Flow?
Data Query refers to queries in Power Query Editor, while Data Flow is used to transform and reuse data in multiple datasets.
8. What is the difference between Calculated Columns and Measures?
Calculated columns are static and stored in the model, while measures are dynamic and calculated during report interaction.
9. What is Query Folding in Power BI?
A: Query folding optimizes queries by delegating transformations back to the data source to improve performance.
10. What is the difference between RANK and DENSE RANK in SQL?
A: RANK skips numbers for ties, whereas DENSE RANK assigns consecutive ranks even with ties.
11. What are the types of Context in Power BI?
There are three types: Row Context, Filter Context, and Query Context, used to manage how data is filtered and displayed.
12. Give an example of INNER JOIN in SQL.
SELECT * FROM Orders o INNER JOIN Customers c ON o.CustomerID = c.CustomerID;
returns rows where the condition is met.
13. What is the difference between Filter and Slicer in Power BI?
Filters are applied in the backend, while slicers are visual controls for users to filter data interactively on the report.
14. What are the fundamentals of Power BI?
Power BI fundamentals include data modeling, DAX calculations, data visualization, and report sharing through the Power BI Service.
15. What is Row Level Security in Power BI?
It defines rules to control which data users can view in Power BI reports, based on their roles.
16. What are the different types of subscriptions in Power BI Report Server?
Subscriptions include email-based report delivery, SharePoint delivery, and Power BI Service for scheduled data refresh.
Like this post if you need more content like this 👍❤️
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Power BI Cheat Sheet ✍
This Power BI cheatsheet is designed to be your quick reference guide for creating impactful reports and dashboards. Whether you’re a beginner exploring the basics or an experienced developer looking for a handy resource, this cheatsheet covers essential topics.
1. Connecting Data
- Import Data: *Home > Get Data > Select Data Source*
- Direct Query: *Home > Get Data > Select Data Source > Direct Query*
2. Data Transformation
- Power Query Editor: *Home > Transform Data*
- Remove Columns: *Transform > Remove Columns*
- Split Columns: *Transform > Split Column by Delimiter*
- Replace Values: *Transform > Replace Values*
3. Data Modeling
- Create Relationships: *Model > Manage Relationships > New*
- Edit Relationships: *Model > Manage Relationships > Edit*
4. DAX Calculations
- New Measure: *Modeling > New Measure*
- Common DAX Functions:
- SUM: SUM(table[column])
- AVERAGE: AVERAGE(table[column])
- IF: IF(condition, true_value, false_value)
- COUNTROWS: COUNTROWS(table)
- CALCULATE: CALCULATE(expression, filter)
5. Creating Visuals
- Select Visualization: *Visualizations Pane > Select Visual Type*
- Bar Chart: *Bar Chart Icon*
- Pie Chart: *Pie Chart Icon*
- Map Visual: *Map Icon*
6. Formatting Visuals
- Change Colors: *Format > Data Colors*
- Customize Titles: *Format > Title > Text*
- Adjust Axis: *Format > Y-Axis / X-Axis*
7. Filters
- Visual Level Filter: *Filter Pane > Add Filter for Selected Visual*
- Page Level Filter: *Filter Pane > Add Filter for Entire Page*
- Report Level Filter: *Filter Pane > Add Filter for Entire Report*
8. Slicers
- Add Slicer: *Visualizations > Slicer Icon*
- Customize Slicer: *Format > Edit Interactions*
9. Drillthrough
- Add Drillthrough: *Pages > Right Click on Field > Drillthrough*
- Back Button: *Insert > Button > Back Button*
10. Publishing & Sharing
- Publish Report: *Home > Publish > Select Workspace*
- Share Report: *File > Share > Publish to Web or Power BI Service*
11. Dashboards
- Create Dashboard: *Power BI Service > New Dashboard*
- Pin Visuals: *Pin Icon on Visual > Pin to Dashboard*
12. Export Options
- Export to PDF: *File > Export > PDF*
- Export Data: *Visual Options > Export Data*
Hope it helps :)
This Power BI cheatsheet is designed to be your quick reference guide for creating impactful reports and dashboards. Whether you’re a beginner exploring the basics or an experienced developer looking for a handy resource, this cheatsheet covers essential topics.
1. Connecting Data
- Import Data: *Home > Get Data > Select Data Source*
- Direct Query: *Home > Get Data > Select Data Source > Direct Query*
2. Data Transformation
- Power Query Editor: *Home > Transform Data*
- Remove Columns: *Transform > Remove Columns*
- Split Columns: *Transform > Split Column by Delimiter*
- Replace Values: *Transform > Replace Values*
3. Data Modeling
- Create Relationships: *Model > Manage Relationships > New*
- Edit Relationships: *Model > Manage Relationships > Edit*
4. DAX Calculations
- New Measure: *Modeling > New Measure*
- Common DAX Functions:
- SUM: SUM(table[column])
- AVERAGE: AVERAGE(table[column])
- IF: IF(condition, true_value, false_value)
- COUNTROWS: COUNTROWS(table)
- CALCULATE: CALCULATE(expression, filter)
5. Creating Visuals
- Select Visualization: *Visualizations Pane > Select Visual Type*
- Bar Chart: *Bar Chart Icon*
- Pie Chart: *Pie Chart Icon*
- Map Visual: *Map Icon*
6. Formatting Visuals
- Change Colors: *Format > Data Colors*
- Customize Titles: *Format > Title > Text*
- Adjust Axis: *Format > Y-Axis / X-Axis*
7. Filters
- Visual Level Filter: *Filter Pane > Add Filter for Selected Visual*
- Page Level Filter: *Filter Pane > Add Filter for Entire Page*
- Report Level Filter: *Filter Pane > Add Filter for Entire Report*
8. Slicers
- Add Slicer: *Visualizations > Slicer Icon*
- Customize Slicer: *Format > Edit Interactions*
9. Drillthrough
- Add Drillthrough: *Pages > Right Click on Field > Drillthrough*
- Back Button: *Insert > Button > Back Button*
10. Publishing & Sharing
- Publish Report: *Home > Publish > Select Workspace*
- Share Report: *File > Share > Publish to Web or Power BI Service*
11. Dashboards
- Create Dashboard: *Power BI Service > New Dashboard*
- Pin Visuals: *Pin Icon on Visual > Pin to Dashboard*
12. Export Options
- Export to PDF: *File > Export > PDF*
- Export Data: *Visual Options > Export Data*
Hope it helps :)
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Forwarded from Coderbroo community
Forwarded from Coderbroo community