Null Values (OLAP)

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Doradus Query Language: Null Values

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A field that has no value for a given object is _null_. Doradus treats null as a "value" that will not match any literal. For example, the clause `Size=0` will be false if the `Size` field is null. This means that `NOT(clause)` will be true if _`clause`_ references a null field.

For Boolean fields, this may be a little unintuitive: assume a Boolean field IsInternal is null for a given object. Then:

IsInternal=true       // false
IsInternal=false      // false
NOT IsInternal=true   // true
NOT IsInternal=false  // true  

In other words, a null Boolean field is neither true nor false, so comparison to either value will always be false, and negating such a comparison will always be true.