In all other programming languages the code has to be along the lines of:
if ((jane.car.colour == james.car.colour) and
(jane.car.colour != null ) and
( null != james.car.colour)):
print ("James and Jane have same car color")
or attempted with a second variable to indicate if value is known
if (( jane.car.colourKnown == True ) and
(james.car.colourKnown == True ) and
( jane.car.colour == james.car.colour)):
print ("James and Jane have same car colour")
I like to think that SQL nulls are the most human way. I think of a scenario: James and Jane each own a car. I don't know neither car colour. Does it mean they are of same colour? All typical programming languages say "Yes". SQL says "I can't tell you, I don't know", and that is what a human would say.
In all other programming languages the code has to be along the lines of:
or attempted with a second variable to indicate if value is known I like to think that SQL nulls are the most human way. I think of a scenario: James and Jane each own a car. I don't know neither car colour. Does it mean they are of same colour? All typical programming languages say "Yes". SQL says "I can't tell you, I don't know", and that is what a human would say.