Interview Questions

How is the Context Filter different from other Filters?

  • Whenever we create a Context Filter, Tableau will create a temporary table for this particular Filter set and other Filters will be applied on the Context Filter data like cascade parameters.
  • Suppose, we have created a Context Filter on countries, USA and India, Tableau will create a temporary table for these two countries’ data and if we have any other Filters other will be applied on these two countries’ data if we don’t have any Context Filter, each record will check for all Filters.

What is the disadvantage of Context Filters?

  • The Context Filter is not frequently changed by the user—if the Filter is changed, the database must be recomputed and the temporary table has to be rewritten, slowing performance.
  • When we set a dimension to context, Tableau creates a temporary table that will require a reload each time the view is initiated. For Excel, Access, and text data sources, the temporary table created is in an Access table format. For SQL Server, MySQL, and Oracle data sources, we must have permission to create a temporary table on our server. For a multidimensional data source, or cubes, temporary tables are not created, and Context Filters defined which Filters are independent and which are dependent.

What is data visualization?

Data visualization refers to the techniques used to communicate data or information by encoding it as visual objects (e.g., points, lines, or bars) contained in graphics.

Why Tableau?

Whether our data is in an on-premise database, a database, a data warehouse, a cloud application, or in an Excel file, we can analyze it with Tableau. We can create views of our data and share it with colleagues, customers, and partners. We can use Tableau to blend it with other data, and we can keep our data up to date automatically.

Can we use non-used columns (columns that are not used in reports but used in data source) in Tableau Filters?

Yes! For example, in a data source, if we have columns like EmpID, EmpName, EmpDept, EmpDsignation, EmpSalary, and in reports we are using EmpName on columns and EmpSalary on rows, we can use EmpDesignation on Filters.

How to combine two Excel files with the same fields but different data (different years)?

Suppose, we have five different Excel files (2007.xls, 2008.xls, … 2011.xls) with the same fields (film name, genre, budget, rating, profitability, etc.) but with data of different years (2007 to 2011). Can someone tell me how can I combine the film name, genre, and profitability so that I can see the visualization of 2007 to 2011 in a single chart?