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.
There are a number of things that can cause a whitish coating or white spots to develop on the tongue, including: 1  Leukoplakia. 2  This condition causes cells in the mouth to grow excessively. 3  That, in turn, leads to the formation of white patches inside the mouth, including on the tongue. So it is important for your dentist to determine the cause of white patches on your tongue. 2  Leukoplakia can develop when the tongue has been irritated, and it is often found in people who use tobacco products. 3  Oral thrush. 4  Also known as candidiasis, oral thrush is a yeast infection that develops inside the mouth.