BIT_AND Function
Performs bitwise logical "and" of the values in RAW r1 with RAW r2 and returns the "anded" result RAW.
BIT_OR Function
Performs bitwise logical "or" of the values in RAW r1 with RAW r2 and returns the "or'd" result RAW.
BIT_XOR Function
Performs bitwise logical "exclusive or" of the values in RAW r1 with RAW r2 and returns the "xor'd" result RAW.
select utl_raw.BIT_AND('1111','0000') from dual;
'0000'
Performs bitwise logical "and" of the values in RAW r1 with RAW r2 and returns the "anded" result RAW.
BIT_OR Function
Performs bitwise logical "or" of the values in RAW r1 with RAW r2 and returns the "or'd" result RAW.
BIT_XOR Function
Performs bitwise logical "exclusive or" of the values in RAW r1 with RAW r2 and returns the "xor'd" result RAW.
select utl_raw.BIT_AND('1111','0000') from dual;
'0000'
在C语言中提供了&, |, ~以及>>,<<等丰富的位操作符，如何通过SQL语句实现对值的类似操作呢？下面给出我们常用的两个函数（其中执行&操作的函数不是吹的，比Oracle 提供的BITAND函数好用，Oracle的函数在操作数较大时会出错），如果大家有类似的需求，只要参照其设计方法，可以很容易完成。1. func_bitoper 我们在工作中常常有这样的需求，要求将某个字段的某一位或多位置为1或0,输入参数in_value是待处理的值，enable_mask表示要将哪几位置为1，如要将bit0和bit2置为1，则enable_mask := POWER(2,0) + POWER(2,2); ,enable_mask为0表示没有需要置为1的位，同理disable_mask表示要将哪几位置为0，如要将bit1和bit3置为0，则disable_mask := POWER(2,1) + POWER(2,3); ,disable_mask为0表示没有需要置为0的位, 返回值为经过位操作后的值。 换句话说，enable动作相当于与enable_mask进行或操作，disable动作相当于与~disable_mask进行与操作。create or replace function func_bitoper(in_value IN NUMBER,enable_mask IN NUMBER,
disable_mask IN NUMBER ) return NUMBER IS
l_enable number;
l_disable number;
i number;
j number;
l_outvalue number;
l_temp number;
begin
l_enable := enable_mask;
l_disable := disable_mask;
l_outvalue := in_value;
-- enable
j := 0;
while l_enable > 0 loop
if MOD(l_enable,2) = 1 then -- to do set work
l_temp :=TRUNC(l_outvalue/POWER(2,j));
if MOD (l_temp,2) = 0 then -- set it to 1
l_outvalue := l_outvalue + POWER(2,j);
end if;
end if;
l_enable := TRUNC(l_enable/2);
j := j+1 ;
end loop; -- disable
j := 0;
while l_disable > 0 loop
if MOD(l_disable,2) = 1 then -- to do set work
l_temp :=TRUNC(l_outvalue/POWER(2,j));
if MOD (l_temp,2) = 1 then -- set it to 0
l_outvalue := l_outvalue - POWER(2,j);
end if;
end if;
l_disable := TRUNC(l_disable/2);
j := j+1 ;
end loop; return l_outvalue;
end;
/2. func_and 用于对两个数进行与操作，经常用于判断用户是否有权限等。create or replace function func_and(in_value IN NUMBER,in_mask IN NUMBER)
return number is
i number;
n_result number;
n_value number;
n_mask number;
begin
n_value := in_value;
n_mask := in_mask;
i := 0;
n_result := n_value;
while n_value > 0 loop
if (mod(n_mask,2) = 0) and (mod(n_value,2) = 1) then
n_result := n_result - power(2,i);
end if;
n_value := TRUNC(n_value/2);
n_mask := TRUNC(n_mask/2);
i := i + 1;
end loop;
return n_result;
end;
/