This section describes functions and operators for examining and manipulating bit values. Bitstrings must be of equal length when performing the bitwise operands AND, OR and XOR. When bit shifting, the original length of the string is preserved.
Bitstring Operators
The table below shows the available mathematical operators for BIT type.
| Operator | Description | Example | Result |
|---|---|---|---|
& |
bitwise AND | '10101'::BIT & '10001'::BIT |
10001 |
| |
bitwise OR | '1011'::BIT | '0001'::BIT |
1011 |
xor |
bitwise XOR | xor('101'::BIT, '001'::BIT) |
100 |
~ |
bitwise NOT | ~('101'::BIT) |
010 |
<< |
bitwise shift left | '1001011'::BIT << 3 |
1011000 |
>> |
bitwise shift right | '1001011'::BIT >> 3 |
0001001 |
Bitstring Functions
The table below shows the available scalar functions for BIT type.
| Function | Description | Example | Result |
|---|---|---|---|
bit_length(bitstring) |
Returns the number of bits in the bitstring. | bit_length('1101011'::BIT) |
7 |
length(bitstring) |
Alias for bit_length. |
length('1101011'::BIT) |
7 |
octet_length(bitstring) |
Returns the number of bytes in the bitstring. | octet_length('1101011'::BIT) |
1 |
bit_count(bitstring) |
Returns the number of set bits in the bitstring. | bit_count('1101011'::BIT) |
5 |
get_bit(bitstring, index) |
Extracts the nth bit from bitstring; the first (leftmost) bit is indexed 0. | get_bit('0110010'::BIT, 2) |
1 |
set_bit(bitstring, index, new_value) |
Sets the nth bit in bitstring to newvalue; the first (leftmost) bit is indexed 0. Returns a new bitstring. | set_bit('0110010'::BIT, 2, 0) |
0100010 |
bit_position(substring, bitstring) |
Returns first starting index of the specified substring within bits, or zero if it’s not present. The first (leftmost) bit is indexed 1 | bit_position('010'::BIT, '1110101'::BIT) |
4 |
Bitstring Aggregate Functions
These aggregate functions are available for BIT type.
| Function | Description | Example |
|---|---|---|
bit_and(arg) |
Returns the bitwise AND operation performed on all bitstrings in a given expression. | bit_and(A) |
bit_or(arg) |
Returns the bitwise OR operation performed on all bitstrings in a given expression. | bit_or(A) |
bit_xor(arg) |
Returns the bitwise XOR operation performed on all bitstrings in a given expression. | bit_xor(A) |