MySQL 5.1 英文手册 :: 11.11.1 Bit Functions

MySQL 5.1 Reference Manual :: 11 Functions and Operators :: 11.11 Other Functions :: 11.11.1 Bit Functions
11.11.1. Bit Functions

Table 11.16. Bitwise Functions

Name Description

BIT_COUNT() Return the number of bits that are set

& Bitwise AND

~ Invert bits

| Bitwise OR

^ Bitwise XOR

<< Left shift

>> Right shift

MySQL uses BIGINT (64-bit) arithmetic for bit operations, so these operators have a maximum range of 64 bits.
- |
  
  Bitwise OR:
```
mysql> SELECT 29 | 15;
        -> 31
```
  The result is an unsigned 64-bit integer.
- &
  
  Bitwise AND:
```
mysql> SELECT 29 & 15;
        -> 13
```
  The result is an unsigned 64-bit integer.
- ^
  
  Bitwise XOR:
```
mysql> SELECT 1 ^ 1;
        -> 0
mysql> SELECT 1 ^ 0;
        -> 1
mysql> SELECT 11 ^ 3;
        -> 8
```
  The result is an unsigned 64-bit integer.
- <<
  
  Shifts a longlong (BIGINT) number to the left.
```
mysql> SELECT 1 << 2;
        -> 4
```
  The result is an unsigned 64-bit integer. The value is truncated to 64 bits. In particular, if the shift count is greater or equal to the width of an unsigned 64-bit number, the result is zero.
- >>
  
  Shifts a longlong (BIGINT) number to the right.
```
mysql> SELECT 4 >> 2;
        -> 1
```
  The result is an unsigned 64-bit integer. The value is truncated to 64 bits. In particular, if the shift count is greater or equal to the width of an unsigned 64-bit number, the result is zero.
- ~
  
  Invert all bits.
```
mysql> SELECT 5 & ~1;
        -> 4
```
  The result is an unsigned 64-bit integer.
- BIT_COUNT(N)
  
  Returns the number of bits that are set in the argument N.
```
mysql> SELECT BIT_COUNT(29), BIT_COUNT(b'101010');
        -> 4, 3
```

Name	Description
`BIT_COUNT()`	Return the number of bits that are set
`&`	Bitwise AND
`~`	Invert bits
`\|`	Bitwise OR
`^`	Bitwise XOR
`<<`	Left shift
`>>`	Right shift

MySQL 实验室 因为专注，所以专业。

11.11.1. Bit Functions

MySQL 实验室因为专注，所以专业。