20 July 2022 What is the difference between the Alt and Coalesce functions 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 Alt() and Coalesce() functions in Qlik Sense, and how they differ from each other: The correct answer is B: Coalesce(SizeName, ’Unknown’) AS SizeName The disparity between the answers this week shows that this function is not well known yet, but Coalesce() has made it to Qlik in recent years. And being the correct answer in this question, why is the answer Coalesce() and not any of the others? The difference between Alt and Coalesce in Qlik The main difference between Alt() and Coalesce() is that Coalesce() returns the first non-null value of the given statement, while Alt() returns the first valid number representation. In this case we are looking to fill a text value (small, medium and large) and not a number, so Alt() will not work. Before Coalesce() was added to Qlik, the go to solution would be to write an If-statement to check for empty values, the solution being something almost equal to answer C. However in this example the else statement of the If() expression is omitted, by which we only get ‘unknown’ as result and not the original SizeName. The proper expression should be: If(IsNull(SizeName), ‘Unknown’, SizeName) AS SizeName. Concluding, the Coalesce() function is the more elegant solution in this case. Using just Coalesce(SizeName, ‘Unknown’) AS SizeName. The syntax for Coalesce is as following: Coalesce(Expr1, [Expr2, Expr3, ....], else) For Coalesce() it is possible to give unlimited arguments to compare. When all of these arguments return null the final position in the syntax can be used to give a return value. In the question ‘Unknown’ was used, so we can quickly select this in the front end to check the overall data quality. Other things to consider when using Coalesce() One thing to note is that Coalesce() makes for a great combination with EmptyIsNull(). Since Coalesce() returns the first non null value, we need to make sure that all values are true null. Using EmptyIsNull() transforms all empty values into a null value. So instead of long strings like, IF(LEN((SizeName) = 0, Null(), SizeName) you could use Coalesce(EmptyIsNull(SizeName), ‘Unknown’). That’s it for this week. See you next Friday? More from the Bitmetric team Qlik Cloud Backup Protect your investment in Qlik with daily incremental backups stored in an encrypted environment with redundant storage. Available for as little as 2 Euro per day. Learn more. Masters Summit for Qlik The Masters Summit for Qlik provides the next step in your path to becoming a Qlik specialist. As an extra perk, Bitmetric has secured an over $450 discount just for you! Use code BITMETRIC at checkout. Read more here. Friday Qlik Test Prep Functions Solution How can we help? Barry has over 20 years experience as a Data & Analytics architect, developer, trainer and author. He will gladly help you with any questions you may have. Call us Mail us 13 June 2025 Qlik Extension: Scroll to Object Ever since Qlik introduced extended sheets in June 2018, we at Bitmetric have been fans. The ability to extend a sheet vertically and add visualizations below the fold is a powerful way to present more insights without cluttering the main view. Yet, even after seven years, it still feels like a hidden feature. Many users […] Extension Qlik 2 June 2025 Simplifying Data Integration with TimeXtender At Bitmetric, we believe in making technology work for people, not the other way around. TimeXtender’s approach to data integration fits this philosophy by removing obstacles and giving users practical tools to manage their data. Solution TimeXtender 12 May 2025 Dagelijkse Qlik Ondersteuning: altijd hulp bij data analyse Bij Bitmetric snappen we hoe belangrijk het is dat je Qlik omgeving gewoon goed werkt. Of je nu dagelijks data analyseert of snel wat inzichten nodig hebt, je wilt dat alles soepel verloopt. Daarom staan onze experts elke dag voor je klaar. Van kleine vragen tot ingewikkelde uitdagingen, we helpen je graag verder, zodat jij je kunt focussen op wat echt telt! Qlik
13 June 2025 Qlik Extension: Scroll to Object Ever since Qlik introduced extended sheets in June 2018, we at Bitmetric have been fans. The ability to extend a sheet vertically and add visualizations below the fold is a powerful way to present more insights without cluttering the main view. Yet, even after seven years, it still feels like a hidden feature. Many users […] Extension Qlik
2 June 2025 Simplifying Data Integration with TimeXtender At Bitmetric, we believe in making technology work for people, not the other way around. TimeXtender’s approach to data integration fits this philosophy by removing obstacles and giving users practical tools to manage their data. Solution TimeXtender
12 May 2025 Dagelijkse Qlik Ondersteuning: altijd hulp bij data analyse Bij Bitmetric snappen we hoe belangrijk het is dat je Qlik omgeving gewoon goed werkt. Of je nu dagelijks data analyseert of snel wat inzichten nodig hebt, je wilt dat alles soepel verloopt. Daarom staan onze experts elke dag voor je klaar. Van kleine vragen tot ingewikkelde uitdagingen, we helpen je graag verder, zodat jij je kunt focussen op wat echt telt! Qlik