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.
spot under tongue pierce. Secondly, tongue piercing is another cause of dark spots on tongue and lips. After the tongue piercing has healed, a dark spot is left on the tongue. The piercing also can lead to dark spot on tongue symptoms because the practice promotes fungal infections. More so, at pierce point, normal tongue pigmentation is lost.
White tongue: White spots, patches or coating of the tongue. See detailed information below for a list of 29 causes of White tongue, Symptom Checker, including diseases and drug side effect causes.Â» Review Causes of White tongue: Causes | Symptom Checker Â».he following medical conditions are some of the possible causes of White tongue. There are likely to be other possible causes, so ask your doctor about your symptoms. 1  Oral candidiasis. 2  Candidiasis. 3  Leukoplakia-white tongue or mouth lining. 4  Keratosis pharyngis-usually white lumps on the tonsils.