Top 10 most important interview questions for Tableau developer 2021
1. What are the different types of filters in Tableau?
Tableau filters are used to restrict the data flowing through tableau workbooks, worksheets and dashboards, etc.
There are different types of filters in tableau are as follow:
a. Data source Filter
b. Context filter
c. Extract Filter
d. Dimension Filter
e. Measure Filter
f. Quick Filters
2. What are LOD expressions and explain LOD?
So there are 3 types of LODs:
3. How to optimize the performance of the Tableau dashboard?
1. Remove unused columns or fields in data source.
2. Use extract filters for data sources
3. Use context filters if applicable
4. Use boolean and integer data types rather than using String data type. Computer process boolean and integer data types faster than Strings.
5. Use Min/Max aggregation instead of Average as processing time for average is slower as compared to Min/Max.
6. Remove marks from your sheets.
7. Use continuous data filters.
8. Reduce the use of nested calculations in your visuals.
4. What are Sets, groups, and what are the differences?
Groups: Tableau groups are simply grouping of lower level dimensions to create higher level category.
Difference between Sets and groups:
Sets are created by using conditions while groups don’t require any condition to create it.
Sets are dynamic in nature while Groups are not dynamic.
If we have created a set of Top 5 customers by profit and a group of top 5 customers by profit, then when after some time the profit changes then group values will be as it was and the values of set will be changing and it will show the correct results.
One more difference: We can not use group in calculation while set can be used.
5.What is the difference between a heat map and a tree map?
Tree map Vs Heat map
Data is represented
Data is represented by
It is used for
It is used for
Colors and size of
When their values
6. List all the file extensions in Tableau.
The below ones are few extensions in Tableau:
- Tableau Workbook (.twb)
- Tableau Data extract (.tde)
- Tableau Datasource (.tds)
- Tableau Packaged Datasource (.tdsx)
- Tableau Bookmark (.tbm)
- Tableau Map Source (.tms)
- Tableau Packaged Workbook (.twbx) – zip file containing .twb and external files.
- Tableau Preferences (.tps)
7. How to create the top 5 and bottom 5 customers in a single sheet?
If you want to show the top 5 and bottom 5 customers in the same view then follow below steps:
1. Create a set of top 5 customers.
2. Again create a set of bottom 5 customers.
3. Now, press Ctrl and select both the sets and right click on it. Select create combined set.
4. Name it ‘top and bottom customers’ and include all members of both sets.
5. Now add this field into the filter shelf. Check your view of Customers by profit contains only top 5 and bottom 5 customers.
8. What is a parameter in Tableau and how it differs from filters?
Parameters are dynamic values used to replace the constant values in calculations.
Parameters are like variables which we can used in tableau calculations. That is parameters allows only single value.
So that parameters have single select options in UI except checkboxes, which have multiple selection and not single value selection.
While filters are simple and straightforward to use to restrict the data. It can be applied on dimension and measures directly.
For example, to show the revenue generated by states Maharashtra and Gujrat in country India, we will directly apply filter on States dimension. So that revenue for only Maharashtra and Gujrat will be available in view and we can change the UI options to see the filter like Checkbox, radio button, drop-down, etc.
9. Explain Row Level Security in Tableau.
Row Level Security (RLS) is the process of restricting the data from specific users and allow access to certain users to specific workbooks.