QlikView Interview Questions and Answers

Qlik [pronounced “klik”] (formerly known as Qliktech) provides an end-to-end platform which includes data integration, user-driven business intelligence and conversational analytics. The software company was founded in 1993 in Lund, Sweden and is now based in King of Prussia, Pennsylvania, United States. The company’s main products are QlikView and Qlik Sense, both software for business intelligence and data visualization.

1. What are Aggregate functions?

Ans:

Aggregation functions are the functions that aggregate or bundle your data present in the rows of the table. You can apply mathematical or statistical operations collectively on large data chunks using aggregate functions.

2. What are the 6 different types of Aggregate functions?

Ans:

Six types or categories of aggregate functions are; Basic, String, Counter, Advanced, Statistical and Financial Aggregate Functions.

3. Explain min() and max() aggregate functions.

Ans:

The min() aggregate function returns the minimum numeric value from the set of values evaluated.

On the contrary, max() function returns the maximum numeric value from the set of data values evaluated.

4. What is the difference between the string aggregate functions MinString(), MaxString() and FirstValue(), LastValue()?

Ans:

All four of these functions apply on the string values. The MinString() function returns the first text value from a column/field irrespective of the order in which it loads. Similarly, MaxString() returns the last text value from a field irrespective of the load order. Like if the field in Months, then MinString() returns January and MaxString() returns December.

Whereas, FirstValue() returns the first value that was loaded (i.e. it follows the load order) and LastValue() returns the last value in load order.

5. What do you understand by Kurtosis() and Skew() functions?

Ans:

Kurtosis() and Skew() are a type of statistical aggregate functions. Kurtosis() measures the peak of a frequency distribution curve. Whereas, Skew() measures the symmetry in a statistical distribution curve.

6. What does the QlikView Aggr() function do?

Ans:

The Aggr() or Aggregation function will aggregate over the set of possible records defined by the selection and returns a value resulting from the calculation performed on the data set.

7. Explain QlikView IntervalMatch() and Match() functions.

Ans:

QlikView IntervalMatch() function matches a value from one table with an interval or time value in another table. That is, you can compare the difference in time values in two tables.

QlikView Match() function matches a string expression value with other relevant values. It is more like an advanced search which uses for filter the required data through script command.

8. What are the two types of Match() function?

Ans:

QlikView Match() function is of two types; Match() and Wildmatch().

The difference between both is that in the Match() function the entire string has to type as it is for the system to search it. Like, if you want to search the data in the field Regions, then you must type the expression like,

Match(Regions, ‘Europe’,‘South Asia’).

But in the case of Wildmatch() full strings aren’t to type, instead wild characters can be used for searching.

Wildmatch(Regions, ‘Eu*’,‘S* As*’)

9. What do you understand by Rangesum() function? How is it different from the Sum() function?

Ans:

Rangesum function is used to calculate the sum of a selected set of data or a range of data. The Sum() function can’t apply on a selected lot of data values but the whole of it. Whereas Rangesum() can use according to your preferred set of data and can apply within another function expression and can return the sum of the expression as well.

10. Discuss one scenario where you can use Rank() function.

Ans:

Let us suppose that a car company wants to know the performance of countries in sales. For this, they would want to rank the countries based on sales that occurred in them. For this we will use Rank() function on the total of sales amount for each country. The expression would look something like this, Rank(sum(Sales_in_country)). This would rank the countries from highest to lowest based on total sales value for each. If Australia had sales of 10,00,000 it will rank 1^st. Then if the USA had sales of 9,80,000 then it would rank 2^nd and so on.

11. What is ETL?

Ans:

ETL is short for a data processing method i.e. Extract, Transform and Load. Data is extracted from the data source, transformed into user files and then finally loaded into QlikView for the users to use them.

12. What is the difference between a list box and a multi box?

Ans:

A list box displays all the values of a single table field in the form of a list. It is used to make selections of data values convenient. Whereas, a multi-box is a compressed table showing only the fields on display. You need to click on the Add sign to view data values of each field. So, the main difference between the two is that in a list box you can only get one field displayed but in a multi-box all the fields can display.

13. What is a text box used for?

Ans:

A text box is used to display descriptive text to give information related to the data user is working with.

14. What is a Mekko chart? Which sector are they most useful in?

Ans:

Mekko charts represent data in the form of colored bars of varying sizes or width (according to the magnitude of data value it is representing). Such charts are used in business sectors specifically in market analysis.

15. What is the fundamental difference between a block chart and a mekko chart?

Ans:

Mekko charts represent data values as bars of varying sizes and width whereas block charts represent data values as blocks of varying areas.

16. Explain Gauge charts.

Ans:

A gauge chart in QlikView is used to display information like in a meter gauge. You can decide the highs and lows of values by looking at the gauge needle. Gauge charts display single expression or data value and not the entire dimension. You can put in different expressions for calculating percentage etc. The needlepoint of the gauge changes as soon as you make any selection in the table.

17. What is a QlikView Dashboard?

Ans:

QlikView’s dashboard is a document/sheet or collection of them consisting of different kinds of sheet objects containing the loaded data in QlikView. A user can conduct analysis on the data by representing and visualizing it in different ways and types of sheet objects on the dashboard.

18. What are the different components of a dashboard?

Ans:

Charts, Input Boxes, Selection Boxes, Buttons, Texts or list box Objects, Notes & Comments.

19. What is the difference between SELECT and LOAD statements?

Ans:

Both the statements are used to load data from external sources into QlikView. However, they are fundamentally different and are used in different situations.

LOAD statement used to load data from all sorts of files, from previously loaded data, inline data, auto generated data. Whereas, SELECT statements are used to load data from ODBC or OLE DB data sources. The statements using SELECT are not evaluated by QlikView but evaluated by the ODBC drivers or OLE DB providers.

20. What are the operations that could perform on the data in a Transformation Wizard?

Ans:

Data can transform in five ways in a transformation wizard,

Garbage, Fill, Column, Unwrap, Rotate.

21. What does the Garbage tab do in a transformation wizard?

Ans:

The garbage tab, used to delete the unwanted rows in a table.

22. What function must you choose to add columns in a table?

Ans:

This can be done from the ‘Column’ function of the transformation wizard. Using this function, a new column can add into the table and values from pre-existing fields can enter in the newly added column.

23. What does the Unwrap function do?

Ans:

The Unwrap function undo the operations performed by the Wrap function. The wrap function takes the bottom half of a table and puts it adjacent (on the right section) of the first half. Whereas, the unwrap function takes this right section of the table and puts it back below the upper section of the table.

24. What are the Dimensions?

Ans:

In a table, Dimensions are always the descriptive text values. The fields with informative values like ID, product name, country, category are all Dimensions.

25. What are Measures?

Ans:

Measures are all the numerical values or fields in the table upon which mathematical calculations can perform.

26. What is a Star Schema?

Ans:

A star schema is a way of representing a data model which has a central fact table to which individual dimension tables link. It is a relational database model which represents a multi-dimensional database. It is called a star schema because the entity relationship diagram of the fact table and dimension table looks like a star.

27. Why is the formation of a Synthetic key considered bad in QlikView?

Ans:

In QlikView, if there are several fields in common between two or more than two tables then a table containing the set of composite keys is made. This table is identified by a synthetic key ($Syn key).

However, this approach by QlikView to manage overriding fields is considered as a sign of poorly designed data models. The user must check for logical errors that in turn reflects into the script not making a good data model.

28. How can data be generated automatically in QlikView?

Ans:

QlikView provides a feature called Auto Generated which is used for generating data using the system’s programming.

Using Auto Generated, QlikView’s software creates data automatically following a few commands. Such data which auto generates not load from an external source but create unique. Auto Generated might generate data like 20 random numbers, dates of the 15th week of the year, date and days from the current date to the last of the year etc.

29. What are the different types of tables in QlikView?

Ans:

There are different types of tables which can be used to represent data in a tabular structure. The types of tables available in QlikView are; Straight table, Pivot table, Mapping table, Cross table and a simple table sheet object.

30. What is a cross table? How is it different from transposing a table using a Rotate function?

Ans:

In a cross table, the rows and column switch places from the state they originally were in. In such a table the data values of rows/records repeat themselves for each corresponding column value (if needed). This is not so in the case when we transpose a table using a Rotate option in the Transformation Wizard.

31. What are the unique features of QlikView?

Ans:

(a)Data Association is maintained automatically. 

(b) The structure, data and calculations of a report are all held in the memory (RAM) of the server. 

(c) Data is compressed to 10% of its original size. 

(d) Visual relationship using colors.

32. What is Incremental Load?

Ans:

The concept of loading only the new or changed records from the source into the QlikView document is called Incremental Load.

33. How do you connect QlikView to Database?

Ans:

QlikView can connect to the database using the ODBC connection created for the database.

34. Why do we need a Master Calendar?

Ans:

The Master calendar is required when we want to create some additional date values which are not already captured in the data that is being analyzed. For example finding the quarter to which a given date falls etc.

35. What is Aggr Function?

Ans:

AGGR statement function produces a virtual table, with one expression and grouped by one or more dimensions. The result of this virtual table can then be used by a further outer aggregation function(s).

36. What is the difference between Join and Keep?

Ans:

In case of keeping both the datasets are available in QlikView’s memory while in join the load statements produce only one data set from which you have to choose the columns. Also there is no concept of outer keep whereas we have outer join available in case of joins.

37. What is the Synthetic key, is it good or bad to have?

Ans:

QlikView creates a synthetic key when two or more columns between tables are the same. It does not impact the data or performance but it indicates a flaw in the data model design.

38. Difference between Join and Concatenate?

Ans:

Join gives the resulting records from two tables as records containing columns from both tables. But Concatenate only appends the rows from one table with another.

39. What are Circular loops in QlikView?

Ans:

A circular loop is created when the relationship between two tables can be established both directly and through another third table.

40. What does MonthStart function do?

Ans:

Returns a value corresponding to a timestamp with the first millisecond of the first date of the month containing date.

41. What does Auto Generated Function do?

Ans:

This function auto generates values between a given range of numbers.

42. What is a pivot table in QlikView?

Ans:

Pivot Tables are used to present sum of values across many dimensions available in the data. For example showing the total sales figure for both the months and quarters in a year.

43. Can QlikView extract data from a website? How?

Ans:

Yes. In the QlikView script editor we have the option to extract data from a web file by giving the URL as the input.

44. What is the use of Promote/Demote options in a Table Box property?

Ans:

It allows you to rearrange the columns in the Table box which is displayed in the Sheet.

45. What are the three options available under the Rotate table functionality for data transformation?

Ans:

Rotate Left, Rotate Right and Transpose.

46. What are the parameters required by a Crosstable Wizard to create a cross table?

Ans:

There are three fields required to create a cross table. Qualifier field, Attribute Field and Data Field.

47. What does Partial Reload do?

Ans:

It Executes the current load script, including all script commands, such as Drop Table and reloads data to the active QlikView document. However, only those tables whose load and select statements are preceded by the Replace or Add prefix are reloaded.

48. How can we see the table structures of data loaded to QlikView’s memory?

Ans:

By using the Table Viewer Option under file menu we can see the Tables and their relationships.

49. What is the use of – Export Sheet layout?

Ans:

When we want to preserve the layout of a sheet to be used again, we export the sheet layout which creates a XML file without any data.

50. What is Webview Mode?

Ans:

The WebView mode uses the internal web browser in QlikView to display the document layout as an AJAX page.

51. What is a selection indicator in QlikView Document?

Ans:

A selection indicator is used to indicate the type of association between the data present in different sheet objects. A green dot indicates selected values, blue dot indicates locked values and red dot indicates de-selected values in AND mode.

52. What does *bi* Does text search mean?

Ans:

It searches for any string that contains bi.

53. What is Fuzzy search in QlikView?

Ans:

Fuzzy search finds all the values according to their degree of resemblance to the search string. Which means, even if the spelling does not match character by character, those results will also be shown.

54. What is a Bookmark in QlikView?

Ans:

A bookmark in QlikView captures the selections in all states defined in a QlikView document. It can be saved and accessed later.

55. What is a user bookmark and a shared server bookmark?

Ans:

The User bookmark is saved in the user computer while the shared server bookmark is saved in the server and accessible to all the allowed users.

56. What are the different ways in which the QlikView Alerts can be triggered?

Ans:

The alerts can be triggered in three ways. 

(a) Automatically when there is a change in data 

(b) Manually from a internal macro 

(c) External program running QlikView API.

57. What are the two ways to insert Load statements into script editor?

Ans:

• Form File 
• Inline

58. When do we need to use the option “Force 32 Bit”?

Ans:

When connecting to a database using ODBC, if the data source only provides a 32-bit driver we use this option.

59. What is a hidden script in QlikView?

Ans:

A Hidden script is a part of the script that executes before the execution of a normal script and it is protected by a password.

60. What is Information density in QlikView table Viewer?

Ans:

It is a ratio between the numbers of records with not null values to the total number of records.

61. What is Subset Ratio?

Ans:

It is the ratio between numbers of distinct values found in the table as compared to total number of distinct values in the field whose subset ratio is required.

62. What are the default column names in Inline data load?

Ans:

The default field names when inline data is inserted is – F1,F2,F3 etc. This can be edited.

63. What is the difference between QVX and QVD files?

Ans:

The QVD file is proprietary and optimized for minimum transformations inside QlikView but the QVX file has an open file format which shows both the table structure and the table data in it.

64. What feature does the Fill Tab in data transform wizard provide?

Ans:

The fill feature is used to fill in empty cells with values from adjacent cells.

65. How can we split the data in a table vertically or horizontally?

Ans:

The data in a table can be split by using the unwrap transformation.

66. What is Context cell Expansion in QlikView?

Ans:

Context cell expansion is used to expand the contents of one cell into several cells in the table.

67. What is a binary statement in QlikView?

Ans:

The binary statement is used to load the access and data parts of a QlikView document. It does not load the layout information of the document.

68. Can we store a sound file in a QlikView document?

Ans:

Yes we can. We can store an external file (audio/video etc.) using Bundle prefix in the QlikView document.

69. What is the use of the function IntervalMatch?

Ans:

The IntervalMatch prefix to a Load or Select (SQL) statement is used for linking discrete numeric values to one or more numeric intervals.

70. What does NoConcatenate do?

Ans:

The Noconcatenate function forces two tables with identical fields to be treated as two separate internal tables.

71. What is the difference between NullAsValue and NullAsNull?

Ans:

NullAsValue allows linking of data which are null but NullAsNull treats the null values as missing values and does not allow any linking between such values.

72. How can we get the number of statements which have caused errors during a script execution?

Ans:

Using of ScriptErrorCount system variable.

What is the value of X in the following code?

73. What do you understand about the associative nature of data in QlikView?

Ans:

By associative nature of data, it is meant that all the fields and data field values are associated with each other (the ones loaded in the same document). For example, if there is a table on country wise sales, in a QlikView document related to sales. Then when we select a country, say India, from a column in the table, data values related or linked to sales in India will get filtered by the system. All the other, unrelated/irrelevant information will be deactivated or sorted out.

74. What will you find in the menu bar of QlikView?

Ans:

On the menu bar of QlikView, there are many menus available with the help of which we can adjust the properties, make changes, add new objects in the sheet etc. The options available in the menu bar are:

• File
• Edit
• View
• Selections
• Layout
• Settings
• Bookmarks
• Reports
• Tools
• Object
• Window
• Help

75. What operations can you perform using the Tools menu given in the Menu bar?

Ans:

In the Tools menu we can use the Edit Menu to edit the tools, make different kinds of charts using wizards like Quick Chart Wizard, Time Chart Wizard, Statistics Chart Wizard and Box Plot Wizard. Two other tasks can be managed through this menu which are Alerts and Themes making.

76. On what levels can you manage the settings from the Settings menu?

Ans:

The Settings menu provides managing the settings and properties of three main factors of QlikView which are; User settings or preferences, Document Properties and Sheet Properties. Apart from this, the Settings menu provides an option where we can view all the available variables and expressions used in QlikView.

77. What do you understand by Delimited files? Why are they called CSV files?

Ans:

A delimited file is a simple text file in which the data fields and field values are separated by a comma, semicolon, tabs etc. Such files are called CSV files where CSV is short for Comma Separated Values. CSV files are saved in .csv extension.

78. What are XML files? How can you load XML files into QlikView?

Ans:

XML stands for Extensive Markup Language. It is a markup language for data and contains tags for data values storing structure and meaning of data. XML files carry the extension .xml.

To load an XML file into QlikView, go to the Edit Script the click in Insert option. Next, select Load Statement and then select Load from File option. A dialog box will appear from where data files can be browsed and selected.

79. Can we load Web files into QlikView? If yes, how?

Ans:

Yes, we can load web files into QlikView. It is done through the Script Editor wherein the Data tab an option of ‘Web Files’ is given. Selecting that option will ask for the URL of the web file and the file will be loaded.

80. What are the different types of data load?

Ans:

There are seven different types of load in QlikView.

• Load from files
• Resident Load
• Incremental Load
• Inline Load
• Add Load
• Buffer Load
• Binary Load

81. What are the types of files you can load data from?

Ans:

In the Load from files type of load, data can be loaded using several different file types. These files are Excel files(xls), Dif files, Xml, Kml files, CSV files, web files (html), Qvd and Qvx files.

82. What is Inline data? How can we load it into QlikView?

Ans:

Inline data is the data set that you can define as well as load in QlikView itself. Inline data is created on the spot and is not loaded from an external data file.

To load inline in QlikView, open the Script Editor and select the Insert option. Then select Load Statement followed by selecting Load from Inline. A dialog box having an empty table will open where we can enter our data values.

83. How can we connect to a database from the script editor?

Ans:

At the bottom half of the script editor, a section named Database is present. We can connect to a database by selecting the connection method from ODBC or OLE DB and then clicking on Connect. Then, we have to select a Data Source Name (DSN) from the list of databases available and that database will be connected to QlikView.

84. Name some databases that QlikView can connect to.

Ans:

MySQL, Progress, Oracle, SQL Server, DB2, MS Access, Informix etc.

85. What is Resident Load?

Ans:

When a file or table which has already been loaded and is residing in QlikView’s memory is called again, then it is defined as Resident Load.

87. What is Preceding Load?

Ans:

When data is loaded using the bits of an already existing load statement then it is called Preceding load. First to be loaded in the original load statement followed by the load statement for the preceding load.

88. Explain Binary Load.

Ans:

A binary load is the type of data loading when data is loaded from a QlikView file (Qvw file) into the system’s RAM. The data from Qvw file is loaded in 0s and 1s i.e. in binary. Binary load replicates the data structure and design into another Qvw file.

89. What do you mean by Buffer load? How is it Significant?

Ans:

A buffer load statement is used to transform a file into a QVD file or create and maintain a file as QVD in QlikView’s memory for future use. Such files are created using a Buffer prefix and are typically stored in the user defined location selected through User Preferences > Locations.

90. What do you understand about QVD files?

Ans:

QVD files stands for QlikView Data files. Such data files contain tables having data created in or exported from QlikView. QVD files are exclusive to QlikView and can only be read and written in QlikView.

91. Discuss the importance of QVD files in QlikView.

Ans:

QVD files serve as a storage or container file that stores data for future use. The role of QVD files between the front end and the back end is that of transition files i.e. data files loaded from database and are stored in QlikView’s memory as QVD files so that it is easier and faster to fetch data from memory (as Qvd files) than having to connect every time to the database. At the front end, Qvd files are converted into Qvw files.

92. How are QVD files created?

Ans:

A QVD file is created using a STORE command. It is created while the main data file is loaded into the script. However, the QlikView document or file will be saved separately with a .qvw extension and the QVD file will be saved at the location defined by you in the path with a .qvd extension.

Syntax:

93. What are Sheets in QlikView?

Ans:

---

Sheets divide a QlikView document into several sections. Every document will have at least one sheet and that is named ‘Main’, you can add more if you want and edit their properties from the Sheet Properties option.

94. What are Sheet Objects? Name them.

Ans:

Sheet Objects are the items that display data in a certain way for the user. A dashboard is made using these sheet objects appropriately. There are many kinds of sheet objects available like,

• List box
• Statistics box
• Multi-box
• Table box
• Chart
• Input box
• Current Selection box
• Button
• Text Object
• Line/Arrow Object
• Slider/Calendar Object
• Bookmark Object
• Search Object
• Container

95. How many types of charts can be created in QlikView?

Ans:

There are total 13 types of charts in QlikView and their names are;

Bar chart, Line chart, Combo Chart, Scatter Chart, Mekko Chart, Gauge chart, Pie chart, Funnel chart, Radar chart, Block chart, Grid chart, Straight table chart and Pivot table chart.

96. In what ways can the Script Editor be invoked in QlikView?

Ans:

script Editor can either be invoked by the icon for Edit Script or by shortcut keys Ctrl+E.

97. How can you reload a script?

Ans:

A script can be reloaded after making changes by the shortcut keys Ctrl+R or by the icon given on the toolbar for Reload script.

98. What are some major categories into which QlikView’s functions are divided?

Ans:

• Aggregation
• Date and Time
• Exponential and Logarithmic
• Financial
• General Numeric
• Logical Function
• Mapping Function
• Number Interpretation
• Range
• String
• Trigonometric and Hyperbolic

99. What is the difference between numsum() and numcount() functions?

Ans:

The num sum function returns the sum of the numbers while the num count function returns the total number of numeric values found. For example, if we have 2,4,5 as input, then numsum will return 11 and numcount will return 3.

100. What are the String functions? Name some of them.

Ans:

String functions apply on a string input. Some of the most commonly used string functions are,

• ord(s)
• chr(n)
• len(s)
• capitalize(s)
• evaluate(s)
• left()
• right()

101. Give some date and time functions.

Ans:

Today(), localtime(), month(), year(), makedate(), timezone(), GMT(), day(), week(), month(), year().