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.
Age spots (also called liver spots, brown spots, or solar lentigines) usually appear on the face and hands of people who are over age 50 but it can certainly happen to people who are younger. With the standard American diet prevalent these days, more people under the age of 40 are seeing a spike in liver spots.