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.
HIV rash usually causes blotches and spots on the skin, which are red in people with fair skin, or dark purplish in people with dark skin. The spots may be flat or slightly raised, and tend to be very itchy. The symptoms vary between patients - some get a very severe rash which covers a large area, others only have a very minor rash.