KB47386: Simple derived metric displays are zero if any component values are zero in MicroStrategy Visual Insights 9.x - 10.x

SYMPTOM:  
A simple subtraction derived metric displays as null, rather than the expected calculation value, when any component metric value is set as a null. If either component has a true value, the issue does not occur.
 
STEPS TO REPRODUCE:

• Change tutorial data to have zero as a value for Cost and/or Profit
• Create a report with Year, Category, Cost, and Profit
• Create a Visual Insight document based off of report
• Create a derived metric:
  
   

• Value displays as null       
   

 
 
CAUSE:  
This is working as designed. The engine is unable to determine that a warehouse null should be calculated as a value of zero. Therefore, any calculation with a warehouse null will result in a null value calculation.
 
ACTION: 
Edit the metric with the warehouse null and add "NulltoZero" to the formula:
 

 
TO LEARN MORE:
Related technotes:
KB46866: Derived metric displays null in dynamic text targeted by slice selector with derived element as source in MicroStrategy Analytics Enterprise Web and Developer
KB37937: Analytical Engine returns warehouse nulls when subtracting two timestamps in a derived metric in MicroStrategy Developer 9.x