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.
According to the Mayo Clinic, white tongue happens as a result of overgrown and swollen papillae on the tongue's surface. Bacteria and dead cells that lodge between the papillae cause the white coating. Numerous causes encourage white tongue, including alcohol and tobacco use, fever, dry mouth and mouth breathing, dehydration and poor oral care. Many causes overlap with the causes of bad breath, including bacteria in the mouth, so it's easy to see how the conditions how the conditions intersect.