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.
Median rhomboid glossitis is a condition that can affect your tongue if you have oral thrush. It causes a red, smooth patch or lump to develop in the middle of the top part of your tongue, which can be sore. You're more likely to develop oral thrush if you: have recently taken antibiotics.
A RealAge answered. Yellow tongue usually occurs when the papillae (tiny projections) on the surface of your tongue become enlarged and yellow-colored from bacteria growing in your mouth. Most often, yellow tongue is an early sign of a harmless condition called black, hairy tongue, which is usually brought on by: poor oral hygiene.