Xor运算符如何工作

Question

有人可以解释一下xor运算符在这两种情况下是如何工作的：

UPDATE Derived
Set Derived.IKey = Derived.IKey - 1

FROM    Derived 
        INNER JOIN
        Base
        ON
            Derived.IKey - 1 = Base.IKey
            AND 
            Derived.Number = Base.Number

WHERE   Derived.IKey
IN
      (
              /** Query to get all records which have duplicates in a table but the previous key is not used**/
              SELECT
                Derived.IKey
              FROM
                Derived
              WHERE
                Derived.IKey - 1 NOT IN (SELECT IKey FROM Derived)
              GROUP BY 
                Derived.IKey
              HAVING 
                COUNT(Derived.IKey) > 1
       )

N是立方体的尺寸数。

Answer 1

xor是一个带有跟随真值表的按位运算符：

0 ^ 0 == 0
1 ^ 0 == 1
0 ^ 1 == 1
1 ^ 1 == 0

x中y，x ^ y中的两个数字中的每一位都会发生这种情况。

Answer 2

  

Exclusive-Or; From Wikipedia, the free encyclopedia

     

Exclusive-Or [XOR] 是一种逻辑运算，仅当两个输入不同时才输出true（一个为真，另一个为假）。

     

示例：
  1 xor 1 = 0
  1 xor 0 = 1
  0 xor 1 = 1
  0 xor 0 = 0
  1110 xor 1001 = 0111（这相当于没有携带的添加）