MySQL中默认字符集的设置有四级:服务器级，数据库级，表级 。最终是字段级 的字符集设置。注意前三种均为默认设置，并不代码你的字段最终会使用这个字符集设置。所以我们建议要用show create table table ; 或show full fields from tableName; 来检查当前表中字段的字符集设置。
ALTER DATABASE db_name DEFAULT CHARACTER SET character_name [COLLATE ...];
把表默认的字符集和所有字符列（CHAR,VARCHAR,TEXT）改为新的字符集：
ALTER TABLE tbl_name CONVERT TO CHARACTER SET character_name [COLLATE ...]
如：ALTER TABLE logtest CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;
只是修改表的默认字符集：
ALTER TABLE tbl_name DEFAULT CHARACTER SET character_name [COLLATE...];
如：ALTER TABLE logtest DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci;
修改字段的字符集：
ALTER TABLE tbl_name CHANGE c_name c_name CHARACTER SET character_name [COLLATE ...];
如：ALTER TABLE logtest CHANGE title title VARCHAR(100) CHARACTER SET utf8 COLLATE utf8_general_ci;
查看数据库编码：
SHOW CREATE DATABASE db_name;
查看表编码：
SHOW CREATE TABLE tbl_name;
查看字段编码：
SHOW FULL COLUMNS FROM tbl_name;
ALTER DATABASE db_name DEFAULT CHARACTER SET character_name [COLLATE ...];
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把表默认的字符集和所有字符列（CHAR,VARCHAR,TEXT）改为新的字符集：
ALTER TABLE tbl_name CONVERT TO CHARACTER SET character_name [COLLATE ...]
如：ALTER TABLE logtest CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;
|
只是修改表的默认字符集：
ALTER TABLE tbl_name DEFAULT CHARACTER SET character_name [COLLATE...];
如：ALTER TABLE logtest DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci;
|
修改字段的字符集：
ALTER TABLE tbl_name CHANGE c_name c_name CHARACTER SET character_name [COLLATE ...];
如：ALTER TABLE logtest CHANGE title title VARCHAR(100) CHARACTER SET utf8 COLLATE utf8_general_ci;
|
查看数据库编码：
SHOW CREATE DATABASE db_name;
|
查看表编码：
SHOW CREATE TABLE tbl_name;
|
查看字段编码：
SHOW FULL COLUMNS FROM tbl_name;