9.6. Bit String Functions and Operators
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:
,
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.
Note
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 signextend on the left.