29 June 2022 How to use the Lookup() function in Qlik Sense Share this message Every Friday at Bitmetric we’re posting a new Qlik certification practice question to our LinkedIn company page. Last Friday we asked the following Qlik Data Architect certification practice question about the Lookup() function in Qlik: The correct answer is C: Roller, UMW, Cobretti, Grotti Most of you got this answer right and that is no surprise. Things like vertical lookup, horizontal lookup and maybe even index match must be very familiar topics for many, but why still use Excel when we have Qlik, right? The lookup() function will evaluate a field from the current or a previously loaded table and find the matching field you enter. Or to put it as the syntax: lookup(field_name, match_field_name, match_field_value [, table_name]) To evaluate the right answer let’s visualize what lookup() has exactly done in the figure below: The Lookup() function is told to find the field value of ‘Manufacturer’ in the target table and match this to the field value of ‘ManufacturerID’ in the target table and ‘ManufacturerID’ in the current table. In the last part of the syntax we determine the target table which in this example is ‘ManufacturerData’. After the match is made it is added to the current table as the column ‘Manufacturer’. Please notice that all the input which refer to the target table are given in quotes. This is mandatory since the arguments without quotes refer to the current table. In this example we also immediately notice some of the limitations of lookup(). When Lookup() is being used, it will always return the value based on the load order and if no match is found it will return NULL. So in this example we are missing ManufacturerID = 4, so it returns NULL and since ManufacturerID = 5 is duplicated, it will return Grotti, since that value is loaded first. And hopefully this is the moment many of you hear the alarm bells ring about data quality. There are quite some things to fix in this data model, we agree, and probably lookup shouldn’t even be used here. Other options like ApplyMap() or even a join could just as well be used and are maybe even better, since the performance of lookup() is not known to be the fastest. So why use lookup? The main reason of this example is not to only show the disadvantages of lookup() but also bring us to the advantages. The strength of lookup() doesn’t lie in applying the lookup to whole tables, but more to get single values from a table, for example as use in variables: LET vExcludeManufacturer =Lookup('Manufacturer', 'ManufacturerID', 1, 'ManufacturerData'); LET vExcludeManufacturerID =Lookup('ManufacturerID', 'Manufacturer', 'Roller' , 'ManufacturerData'); These will result in: vExcludeManufacturer = Roller vExcludeManufacturerID = 1 And while this is an example in a very small dataset, the use case for large datasets is quite clear. So to cut it short, while ApplyMap() or Join would be the better and most of the times faster solutions to join fields to another table, Lookup() is a great way to quickly find individual values from a table, for example to use in a variable. That’s it for this week. See you next Friday? Take your Qlik skills to the next level! If you enjoy Qlik, you’ll love the Masters Summit for Qlik. 3 days of Qlik deep dives, peer networking, ready to use resources and much more! See you there! Test your Qlik knowledge! Check out the Friday Qlik Test Prep archive for more Qlik questions and answers. Friday Qlik Test Prep Functions Solution How can we help? Feel free to contact us if you have any comments or questions. Call us Mail us 21 September 2023 Qlik Sense Enterprise for Windows – Critical Security Fix #2 A new security issue in Qlik Sense Enterprise for Windows has been identified. This resolves an incomplete fix for the vulnerability that was reported earlier this month. Patches are available and it is recommended to update your Qlik Sense Enterprise for Windows environment at the earliest possibility. New Release Qlik Security 6 September 2023 Battle Ships & Big Data: join us for some fun! Unleash the Power of Data in the Ultimate Battle Ship Game! Join us at the Big Data Expo for a thrilling experience that blends strategy, competition, and analytics. Discover how data influences gameplay and be part of our research! Plus, dive into the world of data and analytics with the experts from Bitmetric. Don’t miss out! See you at booth 46! Bitmetric Event Qlik Team 29 August 2023 Qlik Sense Enterprise for Windows – Critical Security Fixes Two security issues in Qlik Sense Enterprise for Windows have been identified and patches made available. Details can be found in Security Bulletin Critical Security fixes for Qlik Sense Enterprise for Windows (CVE-2023-41266, CVE-2023-41265). New Release Qlik Security
21 September 2023 Qlik Sense Enterprise for Windows – Critical Security Fix #2 A new security issue in Qlik Sense Enterprise for Windows has been identified. This resolves an incomplete fix for the vulnerability that was reported earlier this month. Patches are available and it is recommended to update your Qlik Sense Enterprise for Windows environment at the earliest possibility. New Release Qlik Security
6 September 2023 Battle Ships & Big Data: join us for some fun! Unleash the Power of Data in the Ultimate Battle Ship Game! Join us at the Big Data Expo for a thrilling experience that blends strategy, competition, and analytics. Discover how data influences gameplay and be part of our research! Plus, dive into the world of data and analytics with the experts from Bitmetric. Don’t miss out! See you at booth 46! Bitmetric Event Qlik Team
29 August 2023 Qlik Sense Enterprise for Windows – Critical Security Fixes Two security issues in Qlik Sense Enterprise for Windows have been identified and patches made available. Details can be found in Security Bulletin Critical Security fixes for Qlik Sense Enterprise for Windows (CVE-2023-41266, CVE-2023-41265). New Release Qlik Security