I have a table called
Phone
Number varchar(32)
Extension varchar(32)
Constraint
Constraint
ALTER TABLE Phone
ADD CONSTRAINT RequirePhone
CHECK (
Number IS NULL AND EXTENSION IS NOT NULL
OR (Number IS NOT NULL AND Extension IS NULL)
);
constraint
Number
Extension
...
OR (Number IS NULL AND Extension IS NULL)
Doesn't your last clause has to be
OR (Number is NOT NULL AND Extension IS NOT NULL)