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.
Also Read: How to get rid of sharp pain in tongue . Causes of blister on tongue. Blisters on the tongue are as a result of wide range of causes. They are named depending on the area of the tongue they affect and the time they may take to clear. The following are some of the many causes of blisters on the tongue: 1. Sexually Transmitted Diseases [STD]