This section describes functions and operators for examining and
manipulating bit strings, that is values of the types
bit and bit varying. Aside from the
usual comparison operators, the operators
shown in Table 9.13 can be used.
Bit string operands of &, |,
and # must be of equal length. When bit
shifting, the original length of the string is preserved, as shown
in the examples.
Table 9.13. Bit String Operators
| Operator | Description | Example | Result |
|---|---|---|---|
|| | concatenation | B'10001' || B'011' | 10001011 |
& | bitwise AND | B'10001' & B'01101' | 00001 |
| | bitwise OR | B'10001' | B'01101' | 11101 |
# | bitwise XOR | B'10001' # B'01101' | 11100 |
~ | bitwise NOT | ~ B'10001' | 01110 |
<< | bitwise shift left | B'10001' << 3 | 01000 |
>> | bitwise shift right | B'10001' >> 2 | 00100 |
The following SQL-standard functions work on bit
strings as well as character strings:
lengthbit_lengthoctet_lengthpositionsubstringoverlay
The following functions work on bit strings as well as binary
strings:
get_bitset_bit
In addition, it is possible to cast integral values to and from type
bit.
Some examples:
44::bit(10) 0000101100 44::bit(3) 100 cast(-44 as bit(12)) 111111010100 '1110'::bit(4)::integer 14
Note that casting to just “bit” means casting to
bit(1), and so will deliver only the least significant
bit of the integer.
Casting an integer to bit(n) copies the rightmost
n bits. Casting an integer to a bit string width wider
than the integer itself will sign-extend on the left.