我想从一个表中选择一个blob col，base64对其进行编码并将其插入另一个表中。有没有办法做到这一点，没有将数据从数据库和我的应用程序中迂回？
答案 0 :(得分：45)
我一直在寻找相同的东西，我刚刚看到MySQL 5.6有一些支持此功能的新字符串函数：TO_BASE64和FROM_BASE64。
答案 1 :(得分：17)
来自http://wi-fizzle.com/downloads/base64.sql的函数在编码字符串为32字节（空格）时包含一些错误，例如BASE64_ENCODE（CONCAT（CHAR（15），CHAR（32）））。这是纠正功能
DELIMITER $$
USE `YOUR DATABASE`$$
DROP TABLE IF EXISTS core_base64_data$$
CREATE TABLE core_base64_data (c CHAR(1) BINARY, val TINYINT)$$
INSERT INTO core_base64_data VALUES
('A',0), ('B',1), ('C',2), ('D',3), ('E',4), ('F',5), ('G',6), ('H',7), ('I',8), ('J',9),
('K',10), ('L',11), ('M',12), ('N',13), ('O',14), ('P',15), ('Q',16), ('R',17), ('S',18), ('T',19),
('U',20), ('V',21), ('W',22), ('X',23), ('Y',24), ('Z',25), ('a',26), ('b',27), ('c',28), ('d',29),
('e',30), ('f',31), ('g',32), ('h',33), ('i',34), ('j',35), ('k',36), ('l',37), ('m',38), ('n',39),
('o',40), ('p',41), ('q',42), ('r',43), ('s',44), ('t',45), ('u',46), ('v',47), ('w',48), ('x',49),
('y',50), ('z',51), ('0',52), ('1',53), ('2',54), ('3',55), ('4',56), ('5',57), ('6',58), ('7',59),
('8',60), ('9',61), ('+',62), ('/',63), ('=',0) $$
DROP FUNCTION IF EXISTS `BASE64_ENCODE`$$
CREATE DEFINER=`YOUR DATABASE`@`%` FUNCTION `BASE64_ENCODE`(input BLOB) RETURNS BLOB
DETERMINISTIC
SQL SECURITY INVOKER
BEGIN
DECLARE ret BLOB DEFAULT '';
DECLARE done TINYINT DEFAULT 0;
IF input IS NULL THEN
RETURN NULL;
END IF;
each_block:
WHILE NOT done DO BEGIN
DECLARE accum_value BIGINT UNSIGNED DEFAULT 0;
DECLARE in_count TINYINT DEFAULT 0;
DECLARE out_count TINYINT;
each_input_char:
WHILE in_count < 3 DO BEGIN
DECLARE first_char BLOB(1);
IF LENGTH(input) = 0 THEN
SET done = 1;
SET accum_value = accum_value << (8 * (3 - in_count));
LEAVE each_input_char;
END IF;
SET first_char = SUBSTRING(input,1,1);
SET input = SUBSTRING(input,2);
SET accum_value = (accum_value << 8) + ASCII(first_char);
SET in_count = in_count + 1;
END; END WHILE;
-- We've now accumulated 24 bits; deaccumulate into base64 characters
-- We have to work from the left, so use the third byte position and shift left
CASE
WHEN in_count = 3 THEN SET out_count = 4;
WHEN in_count = 2 THEN SET out_count = 3;
WHEN in_count = 1 THEN SET out_count = 2;
ELSE RETURN ret;
END CASE;
WHILE out_count > 0 DO BEGIN
BEGIN
DECLARE out_char CHAR(1);
DECLARE base64_getval CURSOR FOR SELECT c FROM core_base64_data WHERE val = (accum_value >> 18);
OPEN base64_getval;
FETCH base64_getval INTO out_char;
CLOSE base64_getval;
SET ret = CONCAT(ret,out_char);
SET out_count = out_count - 1;
SET accum_value = accum_value << 6 & 0xffffff;
END;
END; END WHILE;
CASE
WHEN in_count = 2 THEN SET ret = CONCAT(ret,'=');
WHEN in_count = 1 THEN SET ret = CONCAT(ret,'==');
ELSE BEGIN END;
END CASE;
END; END WHILE;
RETURN ret;
END$$
DELIMITER ;
答案 2 :(得分：7)
SELECT `id`,`name`, TO_BASE64(content) FROM `db`.`upload`
这会将blob值从 content 列转换为base64字符串。 然后你可以用任何你想要的字符串，甚至将它插入另一个表
答案 3 :(得分：5)
看起来没有，虽然it was requested，并且有一个UDF。
编辑：或者...... this。啊。
答案 4 :(得分：5)
对于那些感兴趣的人，这些是迄今为止唯一的选择：
1）使用这些功能：
http://wi-fizzle.com/downloads/base64.sql
2）如果你已经拥有sys_eval UDF，（Linux），你可以这样做：
sys_eval(CONCAT("echo '",myField,"' | base64"));
众所周知，第一种方法很慢。第二个问题是，编码实际上发生在MySQL“外部”，这可能会产生编码问题（除了您使用sys_ *函数添加的安全风险）。
不幸的是，没有UDF编译版本（应该更快），也没有MySQL中的原生支持（Posgresql supports it！）。
似乎MySQL开发团队are not interested in implement it已经存在于其他语言中，这对我来说似乎很愚蠢。
答案 5 :(得分：2)
另一个不需要支持表的自定义实现：
drop function if exists base64_encode;
create function base64_encode(_data blob)
returns text
begin
declare _alphabet char(64) default 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
declare _lim int unsigned default length(_data);
declare _i int unsigned default 0;
declare _chk3 char(6) default '';
declare _chk3int int default 0;
declare _enc text default '';
while _i < _lim do
set _chk3 = rpad(hex(binary substr(_data, _i + 1, 3)), 6, '0');
set _chk3int = conv(_chk3, 16, 10);
set _enc = concat(
_enc
, substr(_alphabet, ((_chk3int >> 18) & 63) + 1, 1)
, if (_lim-_i > 0, substr(_alphabet, ((_chk3int >> 12) & 63) + 1, 1), '=')
, if (_lim-_i > 1, substr(_alphabet, ((_chk3int >> 6) & 63) + 1, 1), '=')
, if (_lim-_i > 2, substr(_alphabet, ((_chk3int >> 0) & 63) + 1, 1), '=')
);
set _i = _i + 3;
end while;
return _enc;
end;
drop function if exists base64_decode;
create function base64_decode(_enc text)
returns blob
begin
declare _alphabet char(64) default 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
declare _lim int unsigned default 0;
declare _i int unsigned default 0;
declare _chr1byte tinyint default 0;
declare _chk4int int default 0;
declare _chk4int_bits tinyint default 0;
declare _dec blob default '';
declare _rem tinyint default 0;
set _enc = trim(_enc);
set _rem = if(right(_enc, 3) = '===', 3, if(right(_enc, 2) = '==', 2, if(right(_enc, 1) = '=', 1, 0)));
set _lim = length(_enc) - _rem;
while _i < _lim
do
set _chr1byte = locate(substr(_enc, _i + 1, 1), binary _alphabet) - 1;
if (_chr1byte > -1)
then
set _chk4int = (_chk4int << 6) | _chr1byte;
set _chk4int_bits = _chk4int_bits + 6;
if (_chk4int_bits = 24 or _i = _lim-1)
then
if (_i = _lim-1 and _chk4int_bits != 24)
then
set _chk4int = _chk4int << 0;
end if;
set _dec = concat(
_dec
, char((_chk4int >> (_chk4int_bits - 8)) & 0xff)
, if(_chk4int_bits > 8, char((_chk4int >> (_chk4int_bits - 16)) & 0xff), '\0')
, if(_chk4int_bits > 16, char((_chk4int >> (_chk4int_bits - 24)) & 0xff), '\0')
);
set _chk4int = 0;
set _chk4int_bits = 0;
end if;
end if;
set _i = _i + 1;
end while;
return substr(_dec, 1, length(_dec) - _rem);
end;
您应该在解码后转换字符集：convert(base64_decode(base64_encode('ёлка')) using utf8)
答案 6 :(得分：1)
如果你需要这个＆lt; 5.6，我跳过这个似乎工作正常的UDF：
答案 7 :(得分：-2)
create table encrypt（username varchar（20），password varbinary（200））
插入加密值（＆＃39; raju＆＃39;，aes_encrypt（＆＃39; kumar＆＃39;，＆＃39; key＆＃39;）） 从加密中选择*，强制转换（aes_decrypt（密码，＆＃39;密钥＆＃39;）为char（40）），其中username =＆＃39; raju＆＃39;;