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 are the flat brown, black or yellow spots that appear on the neck, hands and face. They are primarily caused by sun exposure, and usually start to appear once people hit 40. Age spots are not dangerous in any way, so there is no medical reason to get rid of them.