How to convert a byte string to a number in Oracle?

I want to convert a byte string like '1001' to the integer value 9, is there a standard function for that in Oracle ?

BTW I found a custom solution on http://www开发者_开发技巧.orafaq.com/wiki/Binary

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I was trying this on Oracle using CONNECT BY to convert binary to decimal in simple SELECT statement. Finally got the desired output using below code.

WITH INPUT AS
(SELECT REVERSE('&N') AS X FROM DUAL)
SELECT SUM(TO_NUMBER(SUBSTR(X,LEVEL,1)*POWER(2,LEVEL-1))) AS OUTPUT
FROM INPUT CONNECT BY LEVEL<=LENGTH(X);

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AFAIK there's no a built in function in Oracle for that, though you can use solution provided int he link in your post

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See here for library from Tom Kyte for doing these type conversions.

In this case, you'd have:

select to_dec('1001', 2) from dual;

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"Is there a standard function for that in Oracle?"

There is BIN_TO_NUM which converts a bit vector to its equivalent number.

SET SERVEROUTPUT ON;
DECLARE
  i VARCHAR2(100) := '1001';
  o INT;
BEGIN
  i:= TRIM(BOTH ',' FROM REPLACE(REPLACE(i, '1', '1,'),'0','0,')); 
  EXECUTE IMMEDIATE 'SELECT BIN_TO_NUM('|| i || ') FROM dual' INTO o;
  DBMS_OUTPUT.put_line(i || ' => ' || o);
END;
/

Result:

1,0,0,1 => 9

DBFiddle Demo