BITAND

Syntax

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Description of the illustration ''bitand.gif''

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).