字符类型
类型 | 说明 | N的含义 | 是否有字符集 | 最大长度 |
char(n) | 定长字符 | 字符 | 是 | 255 |
varchar(n) | 变长字符 | 字符 | 是 | 65535 |
binary(n) | 定长二进制字节 | 字节 | 否 | 255 |
varbinary(n) | 变长二进制字节 | 字节 | 否 | 65535 |
tinyblob | 二进制大对象 | 字节 | 否 | 255 |
blob(n) | 二进制大对象 | 字节 | 否 | 65535 |
mediumblob(n) | 二进制大对象 | 字节 | 否 | 16M |
longblob(n) | 二进制大对象 | 字节 | 否 | 4G |
tinytext(n) | 大对象 | 字节 | 是 | 256 |
text(n) | 大对象 | 字节 | 是 | 65535 |
mediumtext(n) | 大对象 | 字节 | 是 | 16M |
longtext(n) | 大对象 | 字节 | 是 | 4G |
char与varchar
CHAR(N)用来保存固定长度的字符，N的范围是0255，请牢记，N表示的是字符，而不是字节。VARCHAR(N)用来保存变长字符，N的范围为0 65536，N同样表示字符。
在超出65536个字节的情况下，可以考虑使用更大的字符类型TEXT或BLOB，两者最大存储长度为4G，其区别是BLOB没有字符集属性，纯属二进制存储。
VARCHAR字符类型，最大能够存储65536个字节，所以在MySQL数据库下，绝大部分场景使用类型VARCHAR就足够了。
字符集
在表结构设计中，除了将列定义为char和varchar用以存储字符以外，还需要额外定义字符对应的字符集，因为每种字符在不同字符集编码下，对应着不同的二进制值。常见的字符集有gbk、utf8，通常推荐把默认字符集设置为utf8。
查看mysql支持的字符集：
mysql> show charset;
+----------+---------------------------------+---------------------+--------+
| Charset | Description | Default collation | Maxlen |
+----------+---------------------------------+---------------------+--------+
| big5 | Big5 Traditional Chinese | big5_chinese_ci | 2 |
| dec8 | DEC West European | dec8_swedish_ci | 1 |
| cp850 | DOS West European | cp850_general_ci | 1 |
| hp8 | HP West European | hp8_english_ci | 1 |
| koi8r | KOI8-R Relcom Russian | koi8r_general_ci | 1 |
| latin1 | cp1252 West European | latin1_swedish_ci | 1 |
| latin2 | ISO 8859-2 Central European | latin2_general_ci | 1 |
| swe7 | 7bit Swedish | swe7_swedish_ci | 1 |
| ascii | US ASCII | ascii_general_ci | 1 |
| ujis | EUC-JP Japanese | ujis_japanese_ci | 3 |
| sjis | Shift-JIS Japanese | sjis_japanese_ci | 2 |
| hebrew | ISO 8859-8 Hebrew | hebrew_general_ci | 1 |
| tis620 | TIS620 Thai | tis620_thai_ci | 1 |
| euckr | EUC-KR Korean | euckr_korean_ci | 2 |
| koi8u | KOI8-U Ukrainian | koi8u_general_ci | 1 |
| gb2312 | GB2312 Simplified Chinese | gb2312_chinese_ci | 2 |
| greek | ISO 8859-7 Greek | greek_general_ci | 1 |
| cp1250 | Windows Central European | cp1250_general_ci | 1 |
| gbk | GBK Simplified Chinese | gbk_chinese_ci | 2 |
| latin5 | ISO 8859-9 Turkish | latin5_turkish_ci | 1 |
| armscii8 | ARMSCII-8 Armenian | armscii8_general_ci | 1 |
| utf8 | UTF-8 Unicode | utf8_general_ci | 3 |
| ucs2 | UCS-2 Unicode | ucs2_general_ci | 2 |
| cp866 | DOS Russian | cp866_general_ci | 1 |
| keybcs2 | DOS Kamenicky Czech-Slovak | keybcs2_general_ci | 1 |
| macce | Mac Central European | macce_general_ci | 1 |
| macroman | Mac West European | macroman_general_ci | 1 |
| cp852 | DOS Central European | cp852_general_ci | 1 |
| latin7 | ISO 8859-13 Baltic | latin7_general_ci | 1 |
| utf8mb4 | UTF-8 Unicode | utf8mb4_general_ci | 4 |
| cp1251 | Windows Cyrillic | cp1251_general_ci | 1 |
| utf16 | UTF-16 Unicode | utf16_general_ci | 4 |
| utf16le | UTF-16LE Unicode | utf16le_general_ci | 4 |
| cp1256 | Windows Arabic | cp1256_general_ci | 1 |
| cp1257 | Windows Baltic | cp1257_general_ci | 1 |
| utf32 | UTF-32 Unicode | utf32_general_ci | 4 |
| binary | Binary pseudo charset | binary | 1 |
| geostd8 | GEOSTD8 Georgian | geostd8_general_ci | 1 |
| cp932 | SJIS for Windows Japanese | cp932_japanese_ci | 2 |
| eucjpms | UJIS for Windows Japanese | eucjpms_japanese_ci | 3 |
| gb18030 | China National Standard GB18030 | gb18030_chinese_ci | 4 |
+----------+---------------------------------+---------------------+--------+
41 rows in set (0.00 sec)而且随着移动互联网的飞速发展，推荐把MySQL的默认字符集设置为UTF8MB4，否则，某些emoji表情字符无法在UTF8字符集下存储，比如emoji 笑脸表情，对应的字符编码为0xF09F988E：
mysql> select cast(0xF09F988E as char charset utf8);
+---------------------------------------+
| cast(0xF09F988E as char charset utf8) |
+---------------------------------------+
| ???? |
+---------------------------------------+
1 row in set (0.00 sec)
mysql> select cast(0xF09F988E as char charset utf8mb4);
+------------------------------------------+
| cast(0xF09F988E as char charset utf8mb4) |
+------------------------------------------+
|
标签：字符,ci,utf8mb4,字符集,mysql,数据类型,MySQL,test,Yes
From： https://blog.51cto.com/u_6784072/6216446