Bit String Functions and Operators
Bit String Operators
Aside from the usual comparison operators, the following operators can be used. Bit string operands of &, |, and # must be of equal length. In case of bit shifting, the original length of the string is preserved by zero padding (if necessary).
||
Description: Connects bit strings.
Example:
openGauss=# SELECT B'10001' || B'011' AS RESULT; result ---------- 10001011 (1 row)
NOTE:
It is recommended that a column have no more than 180 consecutive internal joins. A column with over 180 joins will be split into joined consecutive strings.
Example: str1||str2||str3||str4 is split into (str1||str2)||(str3||str4).&
Description: Specifies the AND operation between bit strings.
Example:
openGauss=# SELECT B'10001' & B'01101' AS RESULT; result -------- 00001 (1 row)|
Description: Specifies the OR operation between bit strings.
Example:
openGauss=# SELECT B'10001' | B'01101' AS RESULT; result -------- 11101 (1 row)#
Description: Specifies the OR operation between bit strings if they are inconsistent. If the same positions in the two bit strings are both 1 or 0, the position returns 0.
Example:
openGauss=# SELECT B'10001' # B'01101' AS RESULT; result -------- 11100 (1 row)~
Description: Specifies the NOT operation between bit strings.
Example:
openGauss=# SELECT ~B'10001'AS RESULT; result ---------- 01110 (1 row)«
Description: Shifts left in a bit string.
Example:
openGauss=# SELECT B'10001' << 3 AS RESULT; result ---------- 01000 (1 row)>>
Description: Shifts right in a bit string.
Example:
openGauss=# SELECT B'10001' >> 2 AS RESULT; result ---------- 00100 (1 row)
The following SQL-standard functions work on bit strings as well as strings: length, bit_length, octet_length, position, substring, and overlay.
The following functions work on bit strings as well as binary strings: get_bit and set_bit. When working with a bit string, these functions number the first (leftmost) bit of the string as bit 0.
In addition, it is possible to convert between integral values and type bit. Example:
openGauss=# SELECT 44::bit(10) AS RESULT;
result
------------
0000101100
(1 row)
openGauss=# SELECT 44::bit(3) AS RESULT;
result
--------
100
(1 row)
openGauss=# SELECT cast(-44 as bit(12)) AS RESULT;
result
--------------
111111010100
(1 row)
openGauss=# SELECT '1110'::bit(4)::integer AS RESULT;
result
--------
14
(1 row)
openGauss=# select substring('10101111'::bit(8), 2);
substring
-----------
0101111
(1 row)