character set：a set of symbols and encoding.
常见的字符集：utf8、utf8mb4、gbk、gb18030
MySQL 推荐使用 utf8mb4 字符集，对比 utf8 字符集，它更加全。
通过 show character set; 命令查看当前 MySQL 支持的所有字符集。
mysql> show character set;+----------+---------------------------------+---------------------+--------+| 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 | -- gbk，表示的字符有限| 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 | -- utf8，最长3字节| 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 | -- utf8 + mobile端字符| 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 | -- gb18030,最长4个字节+----------+---------------------------------+---------------------+--------+41 rows in set (0.00 sec)
collation
collation 的含义是指排序规则，ci（case insensitive）结尾的排序集是不区分大小写的。
mysql> select 'a' = 'A';+-----------+| 'a' = 'A' |+-----------+| 1 | -- 因为大小写无关，所以返回1+-----------+1 row in set (0.00 sec)mysql> select 'a' = 'A ';+-------------+| 'a' = 'A ' |+-------------+| 1 | --加入空格，返回也是1+-------------+1 row in set (0.00 sec)mysql> create table test_ci (a varchar(10), key(a));Query OK, 0 rows affected (0.13 sec)mysql> insert into test_ci values('a');Query OK, 1 row affected (0.02 sec)mysql> insert into test_ci values('A');Query OK, 1 row affected (0.03 sec)mysql> select * from test_ci where a = 'a';+------+| a |+------+| a || A | -- A也被我们查到了+------+2 rows in set (0.00 sec)
上面的情况如果从业务的角度上看，可以很好理解，比如创建一个用户叫做 Tom，你是不希望再创建一个叫做 tom 的用户的。
修改默认的 collation
mysql> set names utf8mb4 collate utf8mb4_bin; -- 当前会话有效Query OK, 0 rows affected (0.00 sec)mysql> select 'a' = 'A';+-----------+| 'a' = 'A' |+-----------+| 0 |+-----------+1 row in set (0.00 sec)
通过 show collation; 命令查看当前 MySQL 支持的 collation。
mysql> show collation;+--------------------------+----------+-----+---------+----------+---------+| Collation | Charset | Id | Default | Compiled | Sortlen |+--------------------------+----------+-----+---------+----------+---------+| big5_chinese_ci | big5 | 1 | Yes | Yes | 1 || big5_bin | big5 | 84 | | Yes | 1 || dec8_swedish_ci | dec8 | 3 | Yes | Yes | 1 || dec8_bin | dec8 | 69 | | Yes | 1 || cp850_general_ci | cp850 | 4 | Yes | Yes | 1 || cp850_bin | cp850 | 80 | | Yes | 1 || hp8_english_ci | hp8 | 6 | Yes | Yes | 1 || hp8_bin | hp8 | 72 | | Yes | 1 || koi8r_general_ci | koi8r | 7 | Yes | Yes | 1 || koi8r_bin | koi8r | 74 | | Yes | 1 || latin1_german1_ci | latin1 | 5 | | Yes | 1 || latin1_swedish_ci | latin1 | 8 | Yes | Yes | 1 || latin1_danish_ci | latin1 | 15 | | Yes | 1 || latin1_german2_ci | latin1 | 31 | | Yes | 2 || latin1_bin | latin1 | 47 | | Yes | 1 || latin1_general_ci | latin1 | 48 | | Yes | 1 || latin1_general_cs | latin1 | 49 | | Yes | 1 || latin1_spanish_ci | latin1 | 94 | | Yes | 1 || latin2_czech_cs | latin2 | 2 | | Yes | 4 || latin2_general_ci | latin2 | 9 | Yes | Yes | 1 || latin2_hungarian_ci | latin2 | 21 | | Yes | 1 || latin2_croatian_ci | latin2 | 27 | | Yes | 1 || latin2_bin | latin2 | 77 | | Yes | 1 || swe7_swedish_ci | swe7 | 10 | Yes | Yes | 1 || swe7_bin | swe7 | 82 | | Yes | 1 || ascii_general_ci | ascii | 11 | Yes | Yes | 1 || ascii_bin | ascii | 65 | | Yes | 1 || ujis_japanese_ci | ujis | 12 | Yes | Yes | 1 || ujis_bin | ujis | 91 | | Yes | 1 || sjis_japanese_ci | sjis | 13 | Yes | Yes | 1 || sjis_bin | sjis | 88 | | Yes | 1 || hebrew_general_ci | hebrew | 16 | Yes | Yes | 1 || hebrew_bin | hebrew | 71 | | Yes | 1 || tis620_thai_ci | tis620 | 18 | Yes | Yes | 4 || tis620_bin | tis620 | 89 | | Yes | 1 || euckr_korean_ci | euckr | 19 | Yes | Yes | 1 || euckr_bin | euckr | 85 | | Yes | 1 || koi8u_general_ci | koi8u | 22 | Yes | Yes | 1 || koi8u_bin | koi8u | 75 | | Yes | 1 || gb2312_chinese_ci | gb2312 | 24 | Yes | Yes | 1 || gb2312_bin | gb2312 | 86 | | Yes | 1 || greek_general_ci | greek | 25 | Yes | Yes | 1 || greek_bin | greek | 70 | | Yes | 1 || cp1250_general_ci | cp1250 | 26 | Yes | Yes | 1 || cp1250_czech_cs | cp1250 | 34 | | Yes | 2 || cp1250_croatian_ci | cp1250 | 44 | | Yes | 1 || cp1250_bin | cp1250 | 66 | | Yes | 1 || cp1250_polish_ci | cp1250 | 99 | | Yes | 1 || gbk_chinese_ci | gbk | 28 | Yes | Yes | 1 || gbk_bin | gbk | 87 | | Yes | 1 || latin5_turkish_ci | latin5 | 30 | Yes | Yes | 1 || latin5_bin | latin5 | 78 | | Yes | 1 || armscii8_general_ci | armscii8 | 32 | Yes | Yes | 1 || armscii8_bin | armscii8 | 64 | | Yes | 1 || utf8_general_ci | utf8 | 33 | Yes | Yes | 1 || utf8_bin | utf8 | 83 | | Yes | 1 || utf8_unicode_ci | utf8 | 192 | | Yes | 8 || utf8_icelandic_ci | utf8 | 193 | | Yes | 8 || utf8_latvian_ci | utf8 | 194 | | Yes | 8 || utf8_romanian_ci | utf8 | 195 | | Yes | 8 || utf8_slovenian_ci | utf8 | 196 | | Yes | 8 || utf8_polish_ci | utf8 | 197 | | Yes | 8 || utf8_estonian_ci | utf8 | 198 | | Yes | 8 || utf8_spanish_ci | utf8 | 199 | | Yes | 8 || utf8_swedish_ci | utf8 | 200 | | Yes | 8 || utf8_turkish_ci | utf8 | 201 | | Yes | 8 || utf8_czech_ci | utf8 | 202 | | Yes | 8 || utf8_danish_ci | utf8 | 203 | | Yes | 8 || utf8_lithuanian_ci | utf8 | 204 | | Yes | 8 || utf8_slovak_ci | utf8 | 205 | | Yes | 8 || utf8_spanish2_ci | utf8 | 206 | | Yes | 8 || utf8_roman_ci | utf8 | 207 | | Yes | 8 || utf8_persian_ci | utf8 | 208 | | Yes | 8 || utf8_esperanto_ci | utf8 | 209 | | Yes | 8 || utf8_hungarian_ci | utf8 | 210 | | Yes | 8 || utf8_sinhala_ci | utf8 | 211 | | Yes | 8 || utf8_german2_ci | utf8 | 212 | | Yes | 8 || utf8_croatian_ci | utf8 | 213 | | Yes | 8 || utf8_unicode_520_ci | utf8 | 214 | | Yes | 8 || utf8_vietnamese_ci | utf8 | 215 | | Yes | 8 || utf8_general_mysql500_ci | utf8 | 223 | | Yes | 1 || ucs2_general_ci | ucs2 | 35 | Yes | Yes | 1 || ucs2_bin | ucs2 | 90 | | Yes | 1 || ucs2_unicode_ci | ucs2 | 128 | | Yes | 8 || ucs2_icelandic_ci | ucs2 | 129 | | Yes | 8 || ucs2_latvian_ci | ucs2 | 130 | | Yes | 8 || ucs2_romanian_ci | ucs2 | 131 | | Yes | 8 || ucs2_slovenian_ci | ucs2 | 132 | | Yes | 8 || ucs2_polish_ci | ucs2 | 133 | | Yes | 8 || ucs2_estonian_ci | ucs2 | 134 | | Yes | 8 || ucs2_spanish_ci | ucs2 | 135 | | Yes | 8 || ucs2_swedish_ci | ucs2 | 136 | | Yes | 8 || ucs2_turkish_ci | ucs2 | 137 | | Yes | 8 || ucs2_czech_ci | ucs2 | 138 | | Yes | 8 || ucs2_danish_ci | ucs2 | 139 | | Yes | 8 || ucs2_lithuanian_ci | ucs2 | 140 | | Yes | 8 || ucs2_slovak_ci | ucs2 | 141 | | Yes | 8 || ucs2_spanish2_ci | ucs2 | 142 | | Yes | 8 || ucs2_roman_ci | ucs2 | 143 | | Yes | 8 || ucs2_persian_ci | ucs2 | 144 | | Yes | 8 || ucs2_esperanto_ci | ucs2 | 145 | | Yes | 8 || ucs2_hungarian_ci | ucs2 | 146 | | Yes | 8 || ucs2_sinhala_ci | ucs2 | 147 | | Yes | 8 || ucs2_german2_ci | ucs2 | 148 | | Yes | 8 || ucs2_croatian_ci | ucs2 | 149 | | Yes | 8 || ucs2_unicode_520_ci | ucs2 | 150 | | Yes | 8 || ucs2_vietnamese_ci | ucs2 | 151 | | Yes | 8 || ucs2_general_mysql500_ci | ucs2 | 159 | | Yes | 1 || cp866_general_ci | cp866 | 36 | Yes | Yes | 1 || cp866_bin | cp866 | 68 | | Yes | 1 || keybcs2_general_ci | keybcs2 | 37 | Yes | Yes | 1 || keybcs2_bin | keybcs2 | 73 | | Yes | 1 || macce_general_ci | macce | 38 | Yes | Yes | 1 || macce_bin | macce | 43 | | Yes | 1 || macroman_general_ci | macroman | 39 | Yes | Yes | 1 || macroman_bin | macroman | 53 | | Yes | 1 || cp852_general_ci | cp852 | 40 | Yes | Yes | 1 || cp852_bin | cp852 | 81 | | Yes | 1 || latin7_estonian_cs | latin7 | 20 | | Yes | 1 || latin7_general_ci | latin7 | 41 | Yes | Yes | 1 || latin7_general_cs | latin7 | 42 | | Yes | 1 || latin7_bin | latin7 | 79 | | Yes | 1 || utf8mb4_general_ci | utf8mb4 | 45 | Yes | Yes | 1 || utf8mb4_bin | utf8mb4 | 46 | | Yes | 1 || utf8mb4_unicode_ci | utf8mb4 | 224 | | Yes | 8 || utf8mb4_icelandic_ci | utf8mb4 | 225 | | Yes | 8 || utf8mb4_latvian_ci | utf8mb4 | 226 | | Yes | 8 || utf8mb4_romanian_ci | utf8mb4 | 227 | | Yes | 8 || utf8mb4_slovenian_ci | utf8mb4 | 228 | | Yes | 8 || utf8mb4_polish_ci | utf8mb4 | 229 | | Yes | 8 || utf8mb4_estonian_ci | utf8mb4 | 230 | | Yes | 8 || utf8mb4_spanish_ci | utf8mb4 | 231 | | Yes | 8 || utf8mb4_swedish_ci | utf8mb4 | 232 | | Yes | 8 || utf8mb4_turkish_ci | utf8mb4 | 233 | | Yes | 8 || utf8mb4_czech_ci | utf8mb4 | 234 | | Yes | 8 || utf8mb4_danish_ci | utf8mb4 | 235 | | Yes | 8 || utf8mb4_lithuanian_ci | utf8mb4 | 236 | | Yes | 8 || utf8mb4_slovak_ci | utf8mb4 | 237 | | Yes | 8 || utf8mb4_spanish2_ci | utf8mb4 | 238 | | Yes | 8 || utf8mb4_roman_ci | utf8mb4 | 239 | | Yes | 8 || utf8mb4_persian_ci | utf8mb4 | 240 | | Yes | 8 || utf8mb4_esperanto_ci | utf8mb4 | 241 | | Yes | 8 || utf8mb4_hungarian_ci | utf8mb4 | 242 | | Yes | 8 || utf8mb4_sinhala_ci | utf8mb4 | 243 | | Yes | 8 || utf8mb4_german2_ci | utf8mb4 | 244 | | Yes | 8 || utf8mb4_croatian_ci | utf8mb4 | 245 | | Yes | 8 || utf8mb4_unicode_520_ci | utf8mb4 | 246 | | Yes | 8 || utf8mb4_vietnamese_ci | utf8mb4 | 247 | | Yes | 8 || cp1251_bulgarian_ci | cp1251 | 14 | | Yes | 1 || cp1251_ukrainian_ci | cp1251 | 23 | | Yes | 1 || cp1251_bin | cp1251 | 50 | | Yes | 1 || cp1251_general_ci | cp1251 | 51 | Yes | Yes | 1 || cp1251_general_cs | cp1251 | 52 | | Yes | 1 || utf16_general_ci | utf16 | 54 | Yes | Yes | 1 || utf16_bin | utf16 | 55 | | Yes | 1 || utf16_unicode_ci | utf16 | 101 | | Yes | 8 || utf16_icelandic_ci | utf16 | 102 | | Yes | 8 || utf16_latvian_ci | utf16 | 103 | | Yes | 8 || utf16_romanian_ci | utf16 | 104 | | Yes | 8 || utf16_slovenian_ci | utf16 | 105 | | Yes | 8 || utf16_polish_ci | utf16 | 106 | | Yes | 8 || utf16_estonian_ci | utf16 | 107 | | Yes | 8 || utf16_spanish_ci | utf16 | 108 | | Yes | 8 || utf16_swedish_ci | utf16 | 109 | | Yes | 8 || utf16_turkish_ci | utf16 | 110 | | Yes | 8 || utf16_czech_ci | utf16 | 111 | | Yes | 8 || utf16_danish_ci | utf16 | 112 | | Yes | 8 || utf16_lithuanian_ci | utf16 | 113 | | Yes | 8 || utf16_slovak_ci | utf16 | 114 | | Yes | 8 || utf16_spanish2_ci | utf16 | 115 | | Yes | 8 || utf16_roman_ci | utf16 | 116 | | Yes | 8 || utf16_persian_ci | utf16 | 117 | | Yes | 8 || utf16_esperanto_ci | utf16 | 118 | | Yes | 8 || utf16_hungarian_ci | utf16 | 119 | | Yes | 8 || utf16_sinhala_ci | utf16 | 120 | | Yes | 8 || utf16_german2_ci | utf16 | 121 | | Yes | 8 || utf16_croatian_ci | utf16 | 122 | | Yes | 8 || utf16_unicode_520_ci | utf16 | 123 | | Yes | 8 || utf16_vietnamese_ci | utf16 | 124 | | Yes | 8 || utf16le_general_ci | utf16le | 56 | Yes | Yes | 1 || utf16le_bin | utf16le | 62 | | Yes | 1 || cp1256_general_ci | cp1256 | 57 | Yes | Yes | 1 || cp1256_bin | cp1256 | 67 | | Yes | 1 || cp1257_lithuanian_ci | cp1257 | 29 | | Yes | 1 || cp1257_bin | cp1257 | 58 | | Yes | 1 || cp1257_general_ci | cp1257 | 59 | Yes | Yes | 1 || utf32_general_ci | utf32 | 60 | Yes | Yes | 1 || utf32_bin | utf32 | 61 | | Yes | 1 || utf32_unicode_ci | utf32 | 160 | | Yes | 8 || utf32_icelandic_ci | utf32 | 161 | | Yes | 8 || utf32_latvian_ci | utf32 | 162 | | Yes | 8 || utf32_romanian_ci | utf32 | 163 | | Yes | 8 || utf32_slovenian_ci | utf32 | 164 | | Yes | 8 || utf32_polish_ci | utf32 | 165 | | Yes | 8 || utf32_estonian_ci | utf32 | 166 | | Yes | 8 || utf32_spanish_ci | utf32 | 167 | | Yes | 8 || utf32_swedish_ci | utf32 | 168 | | Yes | 8 || utf32_turkish_ci | utf32 | 169 | | Yes | 8 || utf32_czech_ci | utf32 | 170 | | Yes | 8 || utf32_danish_ci | utf32 | 171 | | Yes | 8 || utf32_lithuanian_ci | utf32 | 172 | | Yes | 8 || utf32_slovak_ci | utf32 | 173 | | Yes | 8 || utf32_spanish2_ci | utf32 | 174 | | Yes | 8 || utf32_roman_ci | utf32 | 175 | | Yes | 8 || utf32_persian_ci | utf32 | 176 | | Yes | 8 || utf32_esperanto_ci | utf32 | 177 | | Yes | 8 || utf32_hungarian_ci | utf32 | 178 | | Yes | 8 || utf32_sinhala_ci | utf32 | 179 | | Yes | 8 || utf32_german2_ci | utf32 | 180 | | Yes | 8 || utf32_croatian_ci | utf32 | 181 | | Yes | 8 || utf32_unicode_520_ci | utf32 | 182 | | Yes | 8 || utf32_vietnamese_ci | utf32 | 183 | | Yes | 8 || binary | binary | 63 | Yes | Yes | 1 || geostd8_general_ci | geostd8 | 92 | Yes | Yes | 1 || geostd8_bin | geostd8 | 93 | | Yes | 1 || cp932_japanese_ci | cp932 | 95 | Yes | Yes | 1 || cp932_bin | cp932 | 96 | | Yes | 1 || eucjpms_japanese_ci | eucjpms | 97 | Yes | Yes | 1 || eucjpms_bin | eucjpms | 98 | | Yes | 1 || gb18030_chinese_ci | gb18030 | 248 | Yes | Yes | 2 || gb18030_bin | gb18030 | 249 | | Yes | 1 || gb18030_unicode_520_ci | gb18030 | 250 | | Yes | 8 |+--------------------------+----------+-----+---------+----------+---------+222 rows in set (0.00 sec)
字符集的设置
MySQL 字符集的指定方式：
- 配置 MySQL 配置文件时候配置参数 character-set-server。
Create Database
mysql> create database aaa charset utf8;Query OK, 1 row affected (0.01 sec)
Create Table
CREATE TABLE `t` (`a` varchar(10) CHARACTER SET utf8 DEFAULT NULL,`b` varchar(10) CHARACTER SET gbk DEFAULT NULL,`c` varchar(10) DEFAULT NULL) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4
通常只要对 MySQL 实例配置字符集就可以了。
collation 在 Create Database 和 Create Table 的时候也可以指定。
作者：殷建卫 链接：https://www.yuque.com/yinjianwei/vyrvkf/lvcmg6 来源：殷建卫 - 架构笔记 著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。
若有收获，就点个赞吧
0 人点赞
