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.
Oral thrush causes thick white or cream-colored deposits, most commonly on the tongue or inner cheeks. The lesions can be painful and may bleed slightly when they are scraped. The infected mucosa of the mouth may appear inflamed and red. Oral thrush is caused by species of Candida fungus.