Instruction
Nicely done! Now it's time to review what we've learned:
- the
IS NULLoperator checks if the column isNULL, - the
IS NOT NULLoperator checks if the column is notNULL, - the
ISNULL()function findsNULLs and replaces them with the value given in the second argument, - the
NULLIF(x, y)function returnsNULLifx = yandxotherwise, COALESCE(x, y, ...)returns the first non-NULLargument or replaces aNULLwith the value given in the second argument.
Are you ready for a short quiz?
Exercise
Click to continue.



