Syntax
Purpose
The BITAND
function treats its inputs and its output as vectors of bits; the output is the bitwise AND
of the inputs.
The types of expr1
and expr2
are NUMBER
, and the result is of type NUMBER
. If either argument to BITAND
is NULL
, the result is NULL
.
The arguments must be in the range -(2^{(n-1)}) .. ((2^{(n-1)})-1). If an argument is out of this range, the result is undefined.
The result is computed in several steps. First, each argument A is replaced with the value SIGN(A)*FLOOR(ABS(A))
. This conversion has the effect of truncating each argument towards zero. Next, each argument A (which must now be an integer value) is converted to an n-bit two's complement binary integer value. The two bit values are combined using a bitwise AND
operation. Finally, the resulting n-bit two's complement value is converted back to NUMBER
.
Notes on the BITAND Function
The current implementation of BITAND
defines n
= 128.
PL/SQL supports an overload of BITAND
for which the types of the inputs and of the result are all BINARY_INTEGER
and for which n
= 32.
Examples
The following example performs an AND
operation on the numbers 6 (binary 1,1,0) and 3 (binary 0,1,1):
SELECT BITAND(6,3) FROM DUAL; BITAND(6,3) ----------- 2
This is the same as the following example, which shows the binary values of 6 and 3. The BITAND
function operates only on the significant digits of the binary values:
SELECT BITAND( BIN_TO_NUM(1,1,0), BIN_TO_NUM(0,1,1)) "Binary" FROM DUAL; Binary ---------- 2
Refer to the example for BIN_TO_NUM for information on encoding multiple values in a single column value.
The following example supposes that the order_status
column of the sample table oe.orders
encodes several choices as individual bits within a single numeric value. For example, an order still in the warehouse is represented by a binary value 001 (decimal 1). An order being sent by ground transportation is represented by a binary value 010 (decimal 2). An insured package is represented by a binary value 100 (decimal 4). The example uses the DECODE
function to provide two values for each of the three bits in the order_status
value, one value if the bit is turned on and one if it is turned off.
SELECT order_id, customer_id, order_status, DECODE(BITAND(order_status, 1), 1, 'Warehouse', 'PostOffice') "Location", DECODE(BITAND(order_status, 2), 2, 'Ground', 'Air') "Method", DECODE(BITAND(order_status, 4), 4, 'Insured', 'Certified') "Receipt" FROM orders WHERE sales_rep_id = 160 ORDER BY order_id; ORDER_ID CUSTOMER_ID ORDER_STATUS Location Method Receipt ---------- ----------- ------------ ---------- ------ --------- 2416 104 6 PostOffice Ground Insured 2419 107 3 Warehouse Ground Certified 2420 108 2 PostOffice Ground Certified 2423 145 3 Warehouse Ground Certified 2441 106 5 Warehouse Air Insured 2455 145 7 Warehouse Ground Insured
For the Location
column, BITAND
first compares order_status
with 1 (binary 001). Only significant bit values are compared, so any binary value with a 1 in its rightmost bit (any odd number) will evaluate positively and return 1. Even numbers will return 0. The DECODE
function compares the value returned by BITAND
with 1. If they are both 1, then the location is "Warehouse". If they are different, then the location is "PostOffice".
The Method
and Receipt
columns are calculated similarly. For Method
, BITAND
performs the AND
operation on order_status
and 2 (binary 010). For Receipt
, BITAND
performs the AND
operation on order_status
and 4 (binary 100).