public UnsignedByte subtract(UnsignedByte val) {
        if (val == null || val.value == (byte) 0) {
            return this;
        }
        return valueOf((byte) (this.value - val.value));
    }
Returns an {@code UnsignedByte} whose value is {@code (this - val)}. If the
result would have more than 8 bits, returns the low 8 bits of the result.

@param val value to be subtracted from this unsigned byte, null is treated as
           zero
@return {@code this - val}
clickhouse-data/src/main/java/com/clickhouse/data/value/UnsignedByte.java