A value of NULL indicates that the value is unknown. A value of NULL is different from an empty or zero value. No two null values are equal. Comparisons between two null values, or between a NULL and any other value, return unknown because the value of each NULL is unknown.
Skin Spots on the Face. Most causes of spots on face are harmless. They can be a variety of colors including white, red, black or brown. Common causes include cumulative sun exposure, acne, and skin tags. Keratoacanthoma (hyperkeratosis) is a lesion that grows rapidly, usually on areas exposed to the sun.
Brown spots on skin, are a nightmare for anyone. When exposed to UV rays, skin produces cells called melanocytes. This produces the dark brown pigment called melanin, which turns the skin darker in patches. As these brown spots are mostly formed on face, they are commonly known as face spots.