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.
A lesion can develop on the tongue for a variety of reasons, some of which are avoidable, while others are not. Here are a few causes: TheraBreath toothpaste does not use sodium lauryl sulfate, a harsh detergent known to instigate canker sores. 1  Acidic, spicy, or salty foods.  Changes in hormonal balance.