Using the Previous() function to identify the latest record for a dimensional value
by Ferran Garcia Pagans, Neeraj Kharpate, Philip Hand, James Richardson, Dr. Henric
Qlik Sense: Advanced Data Visualization for Your Organization
- Qlik Sense: Advanced Data Visualization for Your Organization
- Table of Contents
- Qlik Sense: Advanced Data Visualization for Your Organization
- Credits
- Preface
- 1. Module 1
- 1. Qlik Sense® and Data Discovery
- 2. Overview of a Qlik Sense® Application's Life Cycle
- 3. Empowering Next Generation Data Discovery Consumers
- 4. Contributing to Data Discovery
- 5. Authoring Engaging Applications
- 6. Building Qlik Sense® Data Models
- 7. Qlik Sense® Apps in the Cloud
- 8. Extending the Qlik® Analytic Platform
- 9. Administering Qlik Sense®
- 10. Sales Discovery
- 11. Human Resource Discovery
- 12. Travel Expense Discovery
- 13. Demographic Data Discovery
- 2. Module 2
- 1. Getting Started with the Data
- Introduction
- Extracting data from databases and data files
- Extracting data from Web Files
- Activating the Legacy Mode in Qlik Sense® desktop
- Extracting data from custom databases
- Invoking help while in the data load editor or the expression editor
- Previewing data in the Data model viewer
- Creating a Master Library from the Data model viewer
- Using a Master Library in the Edit mode
- 2. Visualizations
- Introduction
- Creating Snapshots
- Creating and adding content to a story
- Adding embedded sheets to the story
- Highlighting the performance measure in a bar chart
- Associating persistent colors to field values
- Using the ColorMix1 function
- Composition
- Relationships
- Comparison
- Distribution
- Structuring visualizations
- 3. Scripting
- Introduction
- Structuring the script
- Efficiently debugging the script
- Packaging the code in script files
- How to use sub routines in Qlik Sense®
- Optimizing the UI calculation speed
- Optimizing the reload time of the application
- Using a For Each loop to load data from multiple files
- Using the Concat function to store multiple field values in a single cell
- 4. Managing Apps and User Interface
- Introduction
- Publishing a Qlik Sense® application created in Qlik Sense® desktop
- Creating private, approved, and community sheets
- Publishing a Qlik Sense® application to Qlik Sense® cloud
- Creating geo maps in Qlik Sense®
- Reference lines in Sales versus Target gauge chart
- Effectively using the KPI object in Qlik Sense®
- Creating Tree Maps
- Creating dimensionless bar charts in Qlik Sense®
- Adding Reference Lines to trendline charts
- Creating text and images
- Applying limitations to charts
- Adding thumbnails – a clear environment
- Navigating many data points in a scatter chart
- 5. Useful Functions
- Introduction
- Using an extended interval match to handle Slowly Changing Dimensions
- Using the Previous() function to identify the latest record for a dimensional value
- Using the NetworkDays() function to calculate the working days in a calendar month
- Using the Concat() function to display a string of field values as a dimension
- Using the Minstring() function to calculate the age of the oldest case in a queue
- Using the Rangesum() function to plot cumulative figures in trendline charts
- Using the Fractile() function to generate quartiles
- Using the FirstSortedValue() function to identify the median in a quartile range
- Using the Declare and Derive functions to generate Calendar fields
- Setting up a moving annual total figure
- Using the For Each loop to extract files from a folder
- Using the Peek() function to create a currency Exchange Rate Calendar
- Using the Peek() function to create a Trial Balance sheet
- 6. Set Analysis
- Introduction
- Cracking the syntax for Set Analysis
- Using flags in Set Analysis
- Using the = sign with variables in Set Analysis
- Point in time using Set Analysis
- Using comparison sets in Set Analysis
- Using embedded functions in Set Analysis
- Creating a multi-measure expression in Set Analysis
- Using search strings inside a set modifier
- Capturing a list of field values using a concat() function in Set Analysis
- Using the element functions P() and E() in Set Analysis
- 7. Extensions in Qlik Sense®
- 8. What's New in Version 2.1.1?
- Introduction
- Using the visual exploration capability in Qlik Sense® 2.1.1
- Defining variables in Qlik Sense®
- Exporting stories to MS PowerPoint
- Using the Qlik Dev Hub in Qlik Sense® 2.1.1
- Using Extension editor in Qlik Dev Hub
- Using Qlik Dev Hub to generate mashups
- Embedding Qlik Sense® application on a website using a single configurator
- Using the Qlik DataMarket
- Creating dynamic charts in Qlik Sense®
- Using Smart Search
- Using smart data load profiling
- Conclusion
- A. Appendix
- 1. Getting Started with the Data
- 3. Module 3
- 1. Getting Ready with Predictive Analytics
- 2. Preparing Your Data
- 3. Exploring and Understanding Your Data
- 4. Creating Your First Qlik Sense Application
- 5. Clustering and Other Unsupervised Learning Methods
- 6. Decision Trees and Other Supervised Learning Methods
- 7. Model Evaluation
- 8. Visualizations, Data Applications, Dashboards, and Data Storytelling
- 9. Developing a Complete Application
- A. Bibliography
- Index
Next
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Using the NetworkDays() function to calculate the working days in a calendar month
In a line-level table, there are multiple records stored for a single dimensional value. For example, an Order Line table will have multiple lines for the same OrderID. Business requirements may warrant us to only consider the first or the latest line for each order. This can be done using the Previous() function available in Qlik Sense.
For the sake of continuity, we will make use of the same script and application as in the previous recipe. We will determine the most recent position for any employee during his or her tenure within the organization.
- Open the data load editor. Change the name of the
EmployeeInttable in the script toEmployeeIntTemp. - Insert the following lines of code after the
EmployeeIntTemptable. If you are copying and pasting the code in the data load editor, make sure that the single quotes are copied in a proper format:EmployeeInt: LOAD *, if([EmployeeID]= previous([EmployeeID]),'No','Yes') AS LatestRecordFlag RESIDENT EmployeeIntTemp ORDER BY [EmployeeID] ASC, PositionFrom DESC; DROP TABLE EmployeeIntTemp;
- Save and load the script.
- Add the field
LatestRecordFlagin the Table object we created in the previous recipe. - Under Sorting, make sure that
PositionFromis promoted to the top. Switch off the Auto sorting feature forPositionFrom. No sorting options should be selected as this will then show thePositionFromdate in the load order. - The table would look like this:
- Select employee Susan Sayce. We can see that there are two positions associated with Susan. If we select the
LatestRecordFlagvalue as Yes, it will only show the latest position for Susan: HR Director.
The LatestRecordFlag can be used in calculations to determine the most recent position of any employee. In our script, we create the LatestRecordFlag using the Previous() function. The Previous() function basically parses the EmployeeID column. If the current record that is being read has the same EmployeeID value as the previous record, then it is flagged as No or else Yes.
The ordering of the fields plays an important role here. Because I wanted to determine the latest position for the employee, the field PositionFrom is arranged in descending order.
We can also make use of the Peek() function in the preceding script. In our example, both Peek() and Previous() would yield the same result. However, Peek() is more effective when the user is targeting a field which has not previously loaded in the table or if the user wants to target a specific row. The Previous() function is more effective when the user wants to compare the current value with the previous value for the field in the input table.
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