Oracle型铸件

Question

How can i do the following in Oracle?

SELECT  (cast field as bit) From Table

Is there a way to conver this into an Oracle statement using something similar to cast or convert?

Answer 1

If what you want is to see is how to do binary,hex,oct conversions, see here . (Tom Kyte rocks)

For example,

SQL> select to_bin( 123 ) bin, to_hex( 123 ) hex, to_oct( 123 ) oct from dual
2  /

BIN             HEX             OCT
--------------- --------------- ---------------
1111011         7B              173

EDIT: If you just wanted to see if a bit was on/off, you could use bitand function (which comes out of the box with Oracle). The to_bin function is also shown here, but not needed to use bitand function.

select to_bin(1234) bin,
  2             bitand(1234,1)+0 bit1,
  3             bitand(1234,2)+0 bit2,
  4             bitand(1234,4)+0 bit3
  5    from dual
  6  /

BIN                BIT1       BIT2       BIT3
------------ ---------- ---------- ----------
10011010010           0          2          0

You can also use power function to get 2nd param value for bitand (2^n). eg, power(2,0), power(2,1), power(2,2)

Answer 2

CREATE OR REPLACE FUNCTION to_base (p_dec IN NUMBER, p_base IN NUMBER)
   RETURN VARCHAR2
IS
   l_str   VARCHAR2 (255) DEFAULT NULL;
   l_num   NUMBER         DEFAULT p_dec;
   l_hex   VARCHAR2 (16)  DEFAULT '0123456789abcdef';
BEGIN
   IF (p_dec IS NULL OR p_base IS NULL)
   THEN
      RETURN NULL;
   END IF;

   IF (TRUNC (p_dec) <> p_dec OR p_dec < 0)
   THEN
      RAISE PROGRAM_ERROR;
   END IF;

   LOOP
      l_str := SUBSTR (l_hex, MOD (l_num, p_base) + 1, 1) || l_str;
      l_num := TRUNC (l_num / p_base);
      EXIT WHEN (l_num = 0);
   END LOOP;

   RETURN l_str;
END to_base;

source: https://www.club-oracle.com/threads/how-to-convert-decimal-to-hexadecimal.16083/

Answer 3

Oracle/PLSQL: Cast Function

The syntax for the cast function is:

cast ( { expr | ( subquery ) | MULTISET ( subquery ) } AS type_name )