The SQL NULL is the term used to represent a missing value. A NULL value in a table is a value in a field that appears to be blank. A field with a NULL value is a field with no value. It is very important to understand that a NULL value is different than a zero value or a field that contains spaces.
Someone with red spots on their tongue may be suffering from geographic tongue, according to Mayo Clinic. Other causes of red spots on the tongue include folic acid and vitamin B-12 deficiencies and scarlet fever, WebMD states. Continue Reading.
Red spots under tongue could be an indication of canker sores, reactions produced by an allergic substance among other causes. Moreover, if you have red or dark red bumps under tongue or on the floor of mouth that have lasted longer or keep appearing see your dentist urgently.