NULL handling in QlikView

    • What is the difference between a NULL and a missing value?
    • How are NULLs propagated in expressions?
    • How does QlikView display NULLs?
    • How do I make NULLs selectable?
    • How do I search for NULLs?
    • Can NULLs be used in key fieds to link tables?
    • What is Ternary Logic?

     

    These quesions and others are answered in this Technical Brief.
    Thank you, mellerbeck and Matthew Fryer for idea and inspiration.

     

    See also

    The Importance of Nothing ,

    NULL – The Invisible Nothing and

    Finding NULL

     

    HIC

     

    2012-12-18: Fixed an error in the section about NULL propagation pertaining to relational operators. Added examples in the same section. /HIC

    2012-12-20: Added information about ideographic space. Changed layout of some truth tables (images). /HIC

    2013-04-46: Added section about How QlikView displays NULLs

    2016-10-13: Corrected a sentence about the result of <Product = {}>