mysql修改表、字段、库的字符集

修改数据库字符集：

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;

此处写utf8_general_ci有时候会报错，直接写utf8即可

alter table logtest convert to character set  utf8;

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;