MySQL castr运算符

Question

下面的查询有没有更短的等价物：(我不能修改这个表)。cast运算符在这里适用吗？

select convert(old_text using utf8) as text,
   convert(rev_timestamp using utf8) as ts,
   convert(rev_user_text using utf8) as user from revision;

更新:表模式是：

CREATE TABLE `revision` (
    `rev_id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
    `rev_page` INT(10) UNSIGNED NOT NULL,
    `rev_text_id` INT(10) UNSIGNED NOT NULL,
    `rev_comment` TINYBLOB NOT NULL,
    `rev_user` INT(10) UNSIGNED NOT NULL DEFAULT '0',
    `rev_user_text` VARCHAR(255) NOT NULL DEFAULT '' COLLATE 'latin1_bin',
    `rev_timestamp` BINARY(14) NOT NULL DEFAULT '\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0',
`old_id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
`old_text` MEDIUMBLOB NOT NULL,
`old_flags` TINYBLOB NOT NULL,
)
COLLATE='latin1_swedish_ci'
ENGINE=InnoDB

Answer 1

最好的做法是修改表并为所需的列设置utf8，而不是每次都转换它们

    ALTER TABLE t MODIFY old_text CHAR(50) CHARACTER SET utf8;
    ALTER TABLE t MODIFY rev_timestamp CHAR(50) CHARACTER SET utf8;
    ALTER TABLE t MODIFY rev_user_text CHAR(50) CHARACTER SET utf8;

然后选择法线。

select old_text  as text, rev_timestamp  as ts, rev_user_text as user 
from revision;

注意:关于char(50)的可以根据需要进行更改。

Answer 2

set names utf8;

SELECT old_text AS text, rev_timestamp AS ts, rev_user_text AS user
FROM revisions;

...but如果你用不同的字符集发送DML，这将会中断。

Answer 3

最简单的修改方法，就是用mysql字符集key修改my.ini文件，

default-character-set = utf8 
character_set_server = utf8

修改后，重启mysql服务，重启服务mysql