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.
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.