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 9.14 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 9.14. 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:
, length
, bit_length
, octet_length
, position
, substring
.overlay
The following functions work on bit strings as well as binary strings:
, get_bit
. When working with a bit string, these functions number the first (leftmost) bit of the string as bit 0.set_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.
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