Oracle MySQL programming self study and interview guide 05-02: view character set and collation

osc_6srwahuo 2020-11-10 12:48:11
oracle mysql programming self study


 Course cover -MySQL-AT A Bao Ge


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  • Preface
  • 1、 View character set
  • 2、 Look at the collation

Preface

MySQL By default latin1(ISO-8859-1) Character set , It's a single byte coded character set . however , Chinese characters are multi byte coded characters , Generally, the corresponding character set is GBKGB18030UTF8.


1、 View character set

1.1、SQL sentence

By using SHOW CHARSET; perhaps SHOW CHARACTER SET; You can view the available character set , As shown below :

mysql> show charset ;
+----------+---------------------------------+---------------------+--------+
| Charset | Description | Default collation | Maxlen |
+----------+---------------------------------+---------------------+--------+
| armscii8 | ARMSCII-8 Armenian | armscii8_general_ci | 1 |
| ascii | US ASCII | ascii_general_ci | 1 |
| big5 | Big5 Traditional Chinese | big5_chinese_ci | 2 |
| binary | Binary pseudo charset | binary | 1 |
| cp1250 | Windows Central European | cp1250_general_ci | 1 |
| cp1251 | Windows Cyrillic | cp1251_general_ci | 1 |
| cp1256 | Windows Arabic | cp1256_general_ci | 1 |
| cp1257 | Windows Baltic | cp1257_general_ci | 1 |
| cp850 | DOS West European | cp850_general_ci | 1 |
| cp852 | DOS Central European | cp852_general_ci | 1 |
| cp866 | DOS Russian | cp866_general_ci | 1 |
| cp932 | SJIS for Windows Japanese | cp932_japanese_ci | 2 |
| dec8 | DEC West European | dec8_swedish_ci | 1 |
| eucjpms | UJIS for Windows Japanese | eucjpms_japanese_ci | 3 |
| euckr | EUC-KR Korean | euckr_korean_ci | 2 |
| gb18030 | China National Standard GB18030 | gb18030_chinese_ci | 4 |
| gb2312 | GB2312 Simplified Chinese | gb2312_chinese_ci | 2 |
| gbk | GBK Simplified Chinese | gbk_chinese_ci | 2 |
| geostd8 | GEOSTD8 Georgian | geostd8_general_ci | 1 |
| greek | ISO 8859-7 Greek | greek_general_ci | 1 |
| hebrew | ISO 8859-8 Hebrew | hebrew_general_ci | 1 |
| hp8 | HP West European | hp8_english_ci | 1 |
| keybcs2 | DOS Kamenicky Czech-Slovak | keybcs2_general_ci | 1 |
| koi8r | KOI8-R Relcom Russian | koi8r_general_ci | 1 |
| koi8u | KOI8-U Ukrainian | koi8u_general_ci | 1 |
| latin1 | cp1252 West European | latin1_swedish_ci | 1 |
| latin2 | ISO 8859-2 Central European | latin2_general_ci | 1 |
| latin5 | ISO 8859-9 Turkish | latin5_turkish_ci | 1 |
| latin7 | ISO 8859-13 Baltic | latin7_general_ci | 1 |
| macce | Mac Central European | macce_general_ci | 1 |
| macroman | Mac West European | macroman_general_ci | 1 |
| sjis | Shift-JIS Japanese | sjis_japanese_ci | 2 |
| swe7 | 7bit Swedish | swe7_swedish_ci | 1 |
| tis620 | TIS620 Thai | tis620_thai_ci | 1 |
| ucs2 | UCS-2 Unicode | ucs2_general_ci | 2 |
| ujis | EUC-JP Japanese | ujis_japanese_ci | 3 |
| utf16 | UTF-16 Unicode | utf16_general_ci | 4 |
| utf16le | UTF-16LE Unicode | utf16le_general_ci | 4 |
| utf32 | UTF-32 Unicode | utf32_general_ci | 4 |
| utf8 | UTF-8 Unicode | utf8_general_ci | 3 |
| utf8mb4 | UTF-8 Unicode | utf8mb4_0900_ai_ci | 4 |
+----------+---------------------------------+---------------------+--------+
41 rows in set (0.12 sec)
mysql> show character set;
+----------+---------------------------------+---------------------+--------+
| Charset | Description | Default collation | Maxlen |
+----------+---------------------------------+---------------------+--------+
| armscii8 | ARMSCII-8 Armenian | armscii8_general_ci | 1 |
| ascii | US ASCII | ascii_general_ci | 1 |
| big5 | Big5 Traditional Chinese | big5_chinese_ci | 2 |
| binary | Binary pseudo charset | binary | 1 |
| cp1250 | Windows Central European | cp1250_general_ci | 1 |
| cp1251 | Windows Cyrillic | cp1251_general_ci | 1 |
| cp1256 | Windows Arabic | cp1256_general_ci | 1 |
| cp1257 | Windows Baltic | cp1257_general_ci | 1 |
| cp850 | DOS West European | cp850_general_ci | 1 |
| cp852 | DOS Central European | cp852_general_ci | 1 |
| cp866 | DOS Russian | cp866_general_ci | 1 |
| cp932 | SJIS for Windows Japanese | cp932_japanese_ci | 2 |
| dec8 | DEC West European | dec8_swedish_ci | 1 |
| eucjpms | UJIS for Windows Japanese | eucjpms_japanese_ci | 3 |
| euckr | EUC-KR Korean | euckr_korean_ci | 2 |
| gb18030 | China National Standard GB18030 | gb18030_chinese_ci | 4 |
| gb2312 | GB2312 Simplified Chinese | gb2312_chinese_ci | 2 |
| gbk | GBK Simplified Chinese | gbk_chinese_ci | 2 |
| geostd8 | GEOSTD8 Georgian | geostd8_general_ci | 1 |
| greek | ISO 8859-7 Greek | greek_general_ci | 1 |
| hebrew | ISO 8859-8 Hebrew | hebrew_general_ci | 1 |
| hp8 | HP West European | hp8_english_ci | 1 |
| keybcs2 | DOS Kamenicky Czech-Slovak | keybcs2_general_ci | 1 |
| koi8r | KOI8-R Relcom Russian | koi8r_general_ci | 1 |
| koi8u | KOI8-U Ukrainian | koi8u_general_ci | 1 |
| latin1 | cp1252 West European | latin1_swedish_ci | 1 |
| latin2 | ISO 8859-2 Central European | latin2_general_ci | 1 |
| latin5 | ISO 8859-9 Turkish | latin5_turkish_ci | 1 |
| latin7 | ISO 8859-13 Baltic | latin7_general_ci | 1 |
| macce | Mac Central European | macce_general_ci | 1 |
| macroman | Mac West European | macroman_general_ci | 1 |
| sjis | Shift-JIS Japanese | sjis_japanese_ci | 2 |
| swe7 | 7bit Swedish | swe7_swedish_ci | 1 |
| tis620 | TIS620 Thai | tis620_thai_ci | 1 |
| ucs2 | UCS-2 Unicode | ucs2_general_ci | 2 |
| ujis | EUC-JP Japanese | ujis_japanese_ci | 3 |
| utf16 | UTF-16 Unicode | utf16_general_ci | 4 |
| utf16le | UTF-16LE Unicode | utf16le_general_ci | 4 |
| utf32 | UTF-32 Unicode | utf32_general_ci | 4 |
| utf8 | UTF-8 Unicode | utf8_general_ci | 3 |
| utf8mb4 | UTF-8 Unicode | utf8mb4_0900_ai_ci | 4 |
+----------+---------------------------------+---------------------+--------+
41 rows in set (0.00 sec)

The above execution results show the character set name (Charset)、 Description information (Description)、 Default proofing set (Default collation) And maximum single character length (Maxlen).

A brief introduction to the selection of common character sets is as follows :

Charset Description Default collation Maxlen
ascii US ASCII( American standard code for information exchange ) ascii_general_ci 1 byte
latin1 cp1252 West European( Western Europe 、 Greek characters ) latin1_swedish_ci 1 byte
latin2 ISO 8859-2 Central European( Central Europe ) latin2_general_ci 1 byte
latin5 ISO 8859-9 Turkish( Turkey ) latin5_turkish_ci 1 byte
latin7 ISO 8859-13 Baltic( the Baltic ) latin7_general_ci 1 byte
big5 Big5 Traditional Chinese( Traditional Chinese ) big5_chinese_ci 2 byte
gb2312 GB2312 Simplified Chinese( Simplified Chinese ) gb2312_chinese_ci 2 byte
gbk GBK Simplified Chinese( Simplified and traditional Chinese 、 Japanese 、 Korean, etc ) gbk_chinese_ci 2 byte
gb18030 China National Standard GB18030 gb18030_chinese_ci 4 byte
utf8 UTF-8 Unicode( In most countries of the world ) utf8_general_ci 3 byte
utf8mb4 UTF-8 Unicode utf8mb4_0900_ai_ci 4 byte

As can be seen from the table above , The more storage space a single character takes up , The more languages supported . and , The character sets listed in the table are downward compatible ASCII, That is to say , If we enter characters in ASCII Within the scope of (0x00~0x7F), that , They're coded exactly the same .

Tips :
For historical reasons ,MySQL Medium utf8 Coding and standard UTF-8(RFC3629) There are some differences . The standard UTF-8(RFC3629) Set a maximum number of characters 4 byte , however MySQL Medium utf8 Set a maximum number of characters 3 Bytes , This leads to UTF8 Some special characters in ( such as emoji Symbol ) Cannot be in MySQL Of utf8 Use in code . To solve this problem ,MySQL5.5.3 The version begins to add utf8mb4 code , Extend a character to 4 byte . therefore , If you want to think about supporting standards UTF-8(RFC3629), You should use utf8mb4 code .

1.2、 Query metadata dictionary table

mysql> select * from information_schema.character_sets;
+--------------------+----------------------+---------------------------------+--------+
| CHARACTER_SET_NAME | DEFAULT_COLLATE_NAME | DESCRIPTION | MAXLEN |
+--------------------+----------------------+---------------------------------+--------+
| big5 | big5_chinese_ci | Big5 Traditional Chinese | 2 |
...
+--------------------+----------------------+---------------------------------+--------+
41 rows in set (0.00 sec)

2、 Look at the collation

2.1、SQL sentence

By using SHOW COLLATION; You can see MySQL Available proofreading sets , As shown below :


mysql> show collation;
+----------------------------+----------+-----+---------+----------+---------+---------------+
| Collation | Charset | Id | Default | Compiled | Sortlen | Pad_attribute |
+----------------------------+----------+-----+---------+----------+---------+---------------+
| armscii8_bin | armscii8 | 64 | | Yes | 1 | PAD SPACE |
| armscii8_general_ci | armscii8 | 32 | Yes | Yes | 1 | PAD SPACE |
| ascii_bin | ascii | 65 | | Yes | 1 | PAD SPACE |
| ascii_general_ci | ascii | 11 | Yes | Yes | 1 | PAD SPACE |
| big5_bin | big5 | 84 | | Yes | 1 | PAD SPACE |
| big5_chinese_ci | big5 | 1 | Yes | Yes | 1 | PAD SPACE |
| binary | binary | 63 | Yes | Yes | 1 | NO PAD |
| cp1250_bin | cp1250 | 66 | | Yes | 1 | PAD SPACE |
| cp1250_croatian_ci | cp1250 | 44 | | Yes | 1 | PAD SPACE |
| cp1250_czech_cs | cp1250 | 34 | | Yes | 2 | PAD SPACE |
| cp1250_general_ci | cp1250 | 26 | Yes | Yes | 1 | PAD SPACE |
| cp1250_polish_ci | cp1250 | 99 | | Yes | 1 | PAD SPACE |
| cp1251_bin | cp1251 | 50 | | Yes | 1 | PAD SPACE |
| cp1251_bulgarian_ci | cp1251 | 14 | | Yes | 1 | PAD SPACE |
| cp1251_general_ci | cp1251 | 51 | Yes | Yes | 1 | PAD SPACE |
| cp1251_general_cs | cp1251 | 52 | | Yes | 1 | PAD SPACE |
| cp1251_ukrainian_ci | cp1251 | 23 | | Yes | 1 | PAD SPACE |
| cp1256_bin | cp1256 | 67 | | Yes | 1 | PAD SPACE |
| cp1256_general_ci | cp1256 | 57 | Yes | Yes | 1 | PAD SPACE |
| cp1257_bin | cp1257 | 58 | | Yes | 1 | PAD SPACE |
| cp1257_general_ci | cp1257 | 59 | Yes | Yes | 1 | PAD SPACE |
| cp1257_lithuanian_ci | cp1257 | 29 | | Yes | 1 | PAD SPACE |
| cp850_bin | cp850 | 80 | | Yes | 1 | PAD SPACE |
| cp850_general_ci | cp850 | 4 | Yes | Yes | 1 | PAD SPACE |
| cp852_bin | cp852 | 81 | | Yes | 1 | PAD SPACE |
| cp852_general_ci | cp852 | 40 | Yes | Yes | 1 | PAD SPACE |
| cp866_bin | cp866 | 68 | | Yes | 1 | PAD SPACE |
| cp866_general_ci | cp866 | 36 | Yes | Yes | 1 | PAD SPACE |
| cp932_bin | cp932 | 96 | | Yes | 1 | PAD SPACE |
| cp932_japanese_ci | cp932 | 95 | Yes | Yes | 1 | PAD SPACE |
| dec8_bin | dec8 | 69 | | Yes | 1 | PAD SPACE |
| dec8_swedish_ci | dec8 | 3 | Yes | Yes | 1 | PAD SPACE |
| eucjpms_bin | eucjpms | 98 | | Yes | 1 | PAD SPACE |
| eucjpms_japanese_ci | eucjpms | 97 | Yes | Yes | 1 | PAD SPACE |
| euckr_bin | euckr | 85 | | Yes | 1 | PAD SPACE |
| euckr_korean_ci | euckr | 19 | Yes | Yes | 1 | PAD SPACE |
| gb18030_bin | gb18030 | 249 | | Yes | 1 | PAD SPACE |
| gb18030_chinese_ci | gb18030 | 248 | Yes | Yes | 2 | PAD SPACE |
| gb18030_unicode_520_ci | gb18030 | 250 | | Yes | 8 | PAD SPACE |
| gb2312_bin | gb2312 | 86 | | Yes | 1 | PAD SPACE |
| gb2312_chinese_ci | gb2312 | 24 | Yes | Yes | 1 | PAD SPACE |
| gbk_bin | gbk | 87 | | Yes | 1 | PAD SPACE |
| gbk_chinese_ci | gbk | 28 | Yes | Yes | 1 | PAD SPACE |
| geostd8_bin | geostd8 | 93 | | Yes | 1 | PAD SPACE |
| geostd8_general_ci | geostd8 | 92 | Yes | Yes | 1 | PAD SPACE |
| greek_bin | greek | 70 | | Yes | 1 | PAD SPACE |
| greek_general_ci | greek | 25 | Yes | Yes | 1 | PAD SPACE |
| hebrew_bin | hebrew | 71 | | Yes | 1 | PAD SPACE |
| hebrew_general_ci | hebrew | 16 | Yes | Yes | 1 | PAD SPACE |
| hp8_bin | hp8 | 72 | | Yes | 1 | PAD SPACE |
| hp8_english_ci | hp8 | 6 | Yes | Yes | 1 | PAD SPACE |
| keybcs2_bin | keybcs2 | 73 | | Yes | 1 | PAD SPACE |
| keybcs2_general_ci | keybcs2 | 37 | Yes | Yes | 1 | PAD SPACE |
| koi8r_bin | koi8r | 74 | | Yes | 1 | PAD SPACE |
| koi8r_general_ci | koi8r | 7 | Yes | Yes | 1 | PAD SPACE |
| koi8u_bin | koi8u | 75 | | Yes | 1 | PAD SPACE |
| koi8u_general_ci | koi8u | 22 | Yes | Yes | 1 | PAD SPACE |
| latin1_bin | latin1 | 47 | | Yes | 1 | PAD SPACE |
| latin1_danish_ci | latin1 | 15 | | Yes | 1 | PAD SPACE |
| latin1_general_ci | latin1 | 48 | | Yes | 1 | PAD SPACE |
| latin1_general_cs | latin1 | 49 | | Yes | 1 | PAD SPACE |
| latin1_german1_ci | latin1 | 5 | | Yes | 1 | PAD SPACE |
| latin1_german2_ci | latin1 | 31 | | Yes | 2 | PAD SPACE |
| latin1_spanish_ci | latin1 | 94 | | Yes | 1 | PAD SPACE |
| latin1_swedish_ci | latin1 | 8 | Yes | Yes | 1 | PAD SPACE |
| latin2_bin | latin2 | 77 | | Yes | 1 | PAD SPACE |
| latin2_croatian_ci | latin2 | 27 | | Yes | 1 | PAD SPACE |
| latin2_czech_cs | latin2 | 2 | | Yes | 4 | PAD SPACE |
| latin2_general_ci | latin2 | 9 | Yes | Yes | 1 | PAD SPACE |
| latin2_hungarian_ci | latin2 | 21 | | Yes | 1 | PAD SPACE |
| latin5_bin | latin5 | 78 | | Yes | 1 | PAD SPACE |
| latin5_turkish_ci | latin5 | 30 | Yes | Yes | 1 | PAD SPACE |
| latin7_bin | latin7 | 79 | | Yes | 1 | PAD SPACE |
| latin7_estonian_cs | latin7 | 20 | | Yes | 1 | PAD SPACE |
| latin7_general_ci | latin7 | 41 | Yes | Yes | 1 | PAD SPACE |
| latin7_general_cs | latin7 | 42 | | Yes | 1 | PAD SPACE |
| macce_bin | macce | 43 | | Yes | 1 | PAD SPACE |
| macce_general_ci | macce | 38 | Yes | Yes | 1 | PAD SPACE |
| macroman_bin | macroman | 53 | | Yes | 1 | PAD SPACE |
| macroman_general_ci | macroman | 39 | Yes | Yes | 1 | PAD SPACE |
| sjis_bin | sjis | 88 | | Yes | 1 | PAD SPACE |
| sjis_japanese_ci | sjis | 13 | Yes | Yes | 1 | PAD SPACE |
| swe7_bin | swe7 | 82 | | Yes | 1 | PAD SPACE |
| swe7_swedish_ci | swe7 | 10 | Yes | Yes | 1 | PAD SPACE |
| tis620_bin | tis620 | 89 | | Yes | 1 | PAD SPACE |
| tis620_thai_ci | tis620 | 18 | Yes | Yes | 4 | PAD SPACE |
| ucs2_bin | ucs2 | 90 | | Yes | 1 | PAD SPACE |
| ucs2_croatian_ci | ucs2 | 149 | | Yes | 8 | PAD SPACE |
| ucs2_czech_ci | ucs2 | 138 | | Yes | 8 | PAD SPACE |
| ucs2_danish_ci | ucs2 | 139 | | Yes | 8 | PAD SPACE |
| ucs2_esperanto_ci | ucs2 | 145 | | Yes | 8 | PAD SPACE |
| ucs2_estonian_ci | ucs2 | 134 | | Yes | 8 | PAD SPACE |
| ucs2_general_ci | ucs2 | 35 | Yes | Yes | 1 | PAD SPACE |
| ucs2_general_mysql500_ci | ucs2 | 159 | | Yes | 1 | PAD SPACE |
| ucs2_german2_ci | ucs2 | 148 | | Yes | 8 | PAD SPACE |
| ucs2_hungarian_ci | ucs2 | 146 | | Yes | 8 | PAD SPACE |
| ucs2_icelandic_ci | ucs2 | 129 | | Yes | 8 | PAD SPACE |
| ucs2_latvian_ci | ucs2 | 130 | | Yes | 8 | PAD SPACE |
| ucs2_lithuanian_ci | ucs2 | 140 | | Yes | 8 | PAD SPACE |
| ucs2_persian_ci | ucs2 | 144 | | Yes | 8 | PAD SPACE |
| ucs2_polish_ci | ucs2 | 133 | | Yes | 8 | PAD SPACE |
| ucs2_romanian_ci | ucs2 | 131 | | Yes | 8 | PAD SPACE |
| ucs2_roman_ci | ucs2 | 143 | | Yes | 8 | PAD SPACE |
| ucs2_sinhala_ci | ucs2 | 147 | | Yes | 8 | PAD SPACE |
| ucs2_slovak_ci | ucs2 | 141 | | Yes | 8 | PAD SPACE |
| ucs2_slovenian_ci | ucs2 | 132 | | Yes | 8 | PAD SPACE |
| ucs2_spanish2_ci | ucs2 | 142 | | Yes | 8 | PAD SPACE |
| ucs2_spanish_ci | ucs2 | 135 | | Yes | 8 | PAD SPACE |
| ucs2_swedish_ci | ucs2 | 136 | | Yes | 8 | PAD SPACE |
| ucs2_turkish_ci | ucs2 | 137 | | Yes | 8 | PAD SPACE |
| ucs2_unicode_520_ci | ucs2 | 150 | | Yes | 8 | PAD SPACE |
| ucs2_unicode_ci | ucs2 | 128 | | Yes | 8 | PAD SPACE |
| ucs2_vietnamese_ci | ucs2 | 151 | | Yes | 8 | PAD SPACE |
| ujis_bin | ujis | 91 | | Yes | 1 | PAD SPACE |
| ujis_japanese_ci | ujis | 12 | Yes | Yes | 1 | PAD SPACE |
| utf16le_bin | utf16le | 62 | | Yes | 1 | PAD SPACE |
| utf16le_general_ci | utf16le | 56 | Yes | Yes | 1 | PAD SPACE |
| utf16_bin | utf16 | 55 | | Yes | 1 | PAD SPACE |
| utf16_croatian_ci | utf16 | 122 | | Yes | 8 | PAD SPACE |
| utf16_czech_ci | utf16 | 111 | | Yes | 8 | PAD SPACE |
| utf16_danish_ci | utf16 | 112 | | Yes | 8 | PAD SPACE |
| utf16_esperanto_ci | utf16 | 118 | | Yes | 8 | PAD SPACE |
| utf16_estonian_ci | utf16 | 107 | | Yes | 8 | PAD SPACE |
| utf16_general_ci | utf16 | 54 | Yes | Yes | 1 | PAD SPACE |
| utf16_german2_ci | utf16 | 121 | | Yes | 8 | PAD SPACE |
| utf16_hungarian_ci | utf16 | 119 | | Yes | 8 | PAD SPACE |
| utf16_icelandic_ci | utf16 | 102 | | Yes | 8 | PAD SPACE |
| utf16_latvian_ci | utf16 | 103 | | Yes | 8 | PAD SPACE |
| utf16_lithuanian_ci | utf16 | 113 | | Yes | 8 | PAD SPACE |
| utf16_persian_ci | utf16 | 117 | | Yes | 8 | PAD SPACE |
| utf16_polish_ci | utf16 | 106 | | Yes | 8 | PAD SPACE |
| utf16_romanian_ci | utf16 | 104 | | Yes | 8 | PAD SPACE |
| utf16_roman_ci | utf16 | 116 | | Yes | 8 | PAD SPACE |
| utf16_sinhala_ci | utf16 | 120 | | Yes | 8 | PAD SPACE |
| utf16_slovak_ci | utf16 | 114 | | Yes | 8 | PAD SPACE |
| utf16_slovenian_ci | utf16 | 105 | | Yes | 8 | PAD SPACE |
| utf16_spanish2_ci | utf16 | 115 | | Yes | 8 | PAD SPACE |
| utf16_spanish_ci | utf16 | 108 | | Yes | 8 | PAD SPACE |
| utf16_swedish_ci | utf16 | 109 | | Yes | 8 | PAD SPACE |
| utf16_turkish_ci | utf16 | 110 | | Yes | 8 | PAD SPACE |
| utf16_unicode_520_ci | utf16 | 123 | | Yes | 8 | PAD SPACE |
| utf16_unicode_ci | utf16 | 101 | | Yes | 8 | PAD SPACE |
| utf16_vietnamese_ci | utf16 | 124 | | Yes | 8 | PAD SPACE |
| utf32_bin | utf32 | 61 | | Yes | 1 | PAD SPACE |
| utf32_croatian_ci | utf32 | 181 | | Yes | 8 | PAD SPACE |
| utf32_czech_ci | utf32 | 170 | | Yes | 8 | PAD SPACE |
| utf32_danish_ci | utf32 | 171 | | Yes | 8 | PAD SPACE |
| utf32_esperanto_ci | utf32 | 177 | | Yes | 8 | PAD SPACE |
| utf32_estonian_ci | utf32 | 166 | | Yes | 8 | PAD SPACE |
| utf32_general_ci | utf32 | 60 | Yes | Yes | 1 | PAD SPACE |
| utf32_german2_ci | utf32 | 180 | | Yes | 8 | PAD SPACE |
| utf32_hungarian_ci | utf32 | 178 | | Yes | 8 | PAD SPACE |
| utf32_icelandic_ci | utf32 | 161 | | Yes | 8 | PAD SPACE |
| utf32_latvian_ci | utf32 | 162 | | Yes | 8 | PAD SPACE |
| utf32_lithuanian_ci | utf32 | 172 | | Yes | 8 | PAD SPACE |
| utf32_persian_ci | utf32 | 176 | | Yes | 8 | PAD SPACE |
| utf32_polish_ci | utf32 | 165 | | Yes | 8 | PAD SPACE |
| utf32_romanian_ci | utf32 | 163 | | Yes | 8 | PAD SPACE |
| utf32_roman_ci | utf32 | 175 | | Yes | 8 | PAD SPACE |
| utf32_sinhala_ci | utf32 | 179 | | Yes | 8 | PAD SPACE |
| utf32_slovak_ci | utf32 | 173 | | Yes | 8 | PAD SPACE |
| utf32_slovenian_ci | utf32 | 164 | | Yes | 8 | PAD SPACE |
| utf32_spanish2_ci | utf32 | 174 | | Yes | 8 | PAD SPACE |
| utf32_spanish_ci | utf32 | 167 | | Yes | 8 | PAD SPACE |
| utf32_swedish_ci | utf32 | 168 | | Yes | 8 | PAD SPACE |
| utf32_turkish_ci | utf32 | 169 | | Yes | 8 | PAD SPACE |
| utf32_unicode_520_ci | utf32 | 182 | | Yes | 8 | PAD SPACE |
| utf32_unicode_ci | utf32 | 160 | | Yes | 8 | PAD SPACE |
| utf32_vietnamese_ci | utf32 | 183 | | Yes | 8 | PAD SPACE |
| utf8mb4_0900_ai_ci | utf8mb4 | 255 | Yes | Yes | 0 | NO PAD |
| utf8mb4_0900_as_ci | utf8mb4 | 305 | | Yes | 0 | NO PAD |
| utf8mb4_0900_as_cs | utf8mb4 | 278 | | Yes | 0 | NO PAD |
| utf8mb4_0900_bin | utf8mb4 | 309 | | Yes | 1 | NO PAD |
| utf8mb4_bin | utf8mb4 | 46 | | Yes | 1 | PAD SPACE |
| utf8mb4_croatian_ci | utf8mb4 | 245 | | Yes | 8 | PAD SPACE |
| utf8mb4_cs_0900_ai_ci | utf8mb4 | 266 | | Yes | 0 | NO PAD |
| utf8mb4_cs_0900_as_cs | utf8mb4 | 289 | | Yes | 0 | NO PAD |
| utf8mb4_czech_ci | utf8mb4 | 234 | | Yes | 8 | PAD SPACE |
| utf8mb4_danish_ci | utf8mb4 | 235 | | Yes | 8 | PAD SPACE |
| utf8mb4_da_0900_ai_ci | utf8mb4 | 267 | | Yes | 0 | NO PAD |
| utf8mb4_da_0900_as_cs | utf8mb4 | 290 | | Yes | 0 | NO PAD |
| utf8mb4_de_pb_0900_ai_ci | utf8mb4 | 256 | | Yes | 0 | NO PAD |
| utf8mb4_de_pb_0900_as_cs | utf8mb4 | 279 | | Yes | 0 | NO PAD |
| utf8mb4_eo_0900_ai_ci | utf8mb4 | 273 | | Yes | 0 | NO PAD |
| utf8mb4_eo_0900_as_cs | utf8mb4 | 296 | | Yes | 0 | NO PAD |
| utf8mb4_esperanto_ci | utf8mb4 | 241 | | Yes | 8 | PAD SPACE |
| utf8mb4_estonian_ci | utf8mb4 | 230 | | Yes | 8 | PAD SPACE |
| utf8mb4_es_0900_ai_ci | utf8mb4 | 263 | | Yes | 0 | NO PAD |
| utf8mb4_es_0900_as_cs | utf8mb4 | 286 | | Yes | 0 | NO PAD |
| utf8mb4_es_trad_0900_ai_ci | utf8mb4 | 270 | | Yes | 0 | NO PAD |
| utf8mb4_es_trad_0900_as_cs | utf8mb4 | 293 | | Yes | 0 | NO PAD |
| utf8mb4_et_0900_ai_ci | utf8mb4 | 262 | | Yes | 0 | NO PAD |
| utf8mb4_et_0900_as_cs | utf8mb4 | 285 | | Yes | 0 | NO PAD |
| utf8mb4_general_ci | utf8mb4 | 45 | | Yes | 1 | PAD SPACE |
| utf8mb4_german2_ci | utf8mb4 | 244 | | Yes | 8 | PAD SPACE |
| utf8mb4_hr_0900_ai_ci | utf8mb4 | 275 | | Yes | 0 | NO PAD |
| utf8mb4_hr_0900_as_cs | utf8mb4 | 298 | | Yes | 0 | NO PAD |
| utf8mb4_hungarian_ci | utf8mb4 | 242 | | Yes | 8 | PAD SPACE |
| utf8mb4_hu_0900_ai_ci | utf8mb4 | 274 | | Yes | 0 | NO PAD |
| utf8mb4_hu_0900_as_cs | utf8mb4 | 297 | | Yes | 0 | NO PAD |
| utf8mb4_icelandic_ci | utf8mb4 | 225 | | Yes | 8 | PAD SPACE |
| utf8mb4_is_0900_ai_ci | utf8mb4 | 257 | | Yes | 0 | NO PAD |
| utf8mb4_is_0900_as_cs | utf8mb4 | 280 | | Yes | 0 | NO PAD |
| utf8mb4_ja_0900_as_cs | utf8mb4 | 303 | | Yes | 0 | NO PAD |
| utf8mb4_ja_0900_as_cs_ks | utf8mb4 | 304 | | Yes | 24 | NO PAD |
| utf8mb4_latvian_ci | utf8mb4 | 226 | | Yes | 8 | PAD SPACE |
| utf8mb4_la_0900_ai_ci | utf8mb4 | 271 | | Yes | 0 | NO PAD |
| utf8mb4_la_0900_as_cs | utf8mb4 | 294 | | Yes | 0 | NO PAD |
| utf8mb4_lithuanian_ci | utf8mb4 | 236 | | Yes | 8 | PAD SPACE |
| utf8mb4_lt_0900_ai_ci | utf8mb4 | 268 | | Yes | 0 | NO PAD |
| utf8mb4_lt_0900_as_cs | utf8mb4 | 291 | | Yes | 0 | NO PAD |
| utf8mb4_lv_0900_ai_ci | utf8mb4 | 258 | | Yes | 0 | NO PAD |
| utf8mb4_lv_0900_as_cs | utf8mb4 | 281 | | Yes | 0 | NO PAD |
| utf8mb4_persian_ci | utf8mb4 | 240 | | Yes | 8 | PAD SPACE |
| utf8mb4_pl_0900_ai_ci | utf8mb4 | 261 | | Yes | 0 | NO PAD |
| utf8mb4_pl_0900_as_cs | utf8mb4 | 284 | | Yes | 0 | NO PAD |
| utf8mb4_polish_ci | utf8mb4 | 229 | | Yes | 8 | PAD SPACE |
| utf8mb4_romanian_ci | utf8mb4 | 227 | | Yes | 8 | PAD SPACE |
| utf8mb4_roman_ci | utf8mb4 | 239 | | Yes | 8 | PAD SPACE |
| utf8mb4_ro_0900_ai_ci | utf8mb4 | 259 | | Yes | 0 | NO PAD |
| utf8mb4_ro_0900_as_cs | utf8mb4 | 282 | | Yes | 0 | NO PAD |
| utf8mb4_ru_0900_ai_ci | utf8mb4 | 306 | | Yes | 0 | NO PAD |
| utf8mb4_ru_0900_as_cs | utf8mb4 | 307 | | Yes | 0 | NO PAD |
| utf8mb4_sinhala_ci | utf8mb4 | 243 | | Yes | 8 | PAD SPACE |
| utf8mb4_sk_0900_ai_ci | utf8mb4 | 269 | | Yes | 0 | NO PAD |
| utf8mb4_sk_0900_as_cs | utf8mb4 | 292 | | Yes | 0 | NO PAD |
| utf8mb4_slovak_ci | utf8mb4 | 237 | | Yes | 8 | PAD SPACE |
| utf8mb4_slovenian_ci | utf8mb4 | 228 | | Yes | 8 | PAD SPACE |
| utf8mb4_sl_0900_ai_ci | utf8mb4 | 260 | | Yes | 0 | NO PAD |
| utf8mb4_sl_0900_as_cs | utf8mb4 | 283 | | Yes | 0 | NO PAD |
| utf8mb4_spanish2_ci | utf8mb4 | 238 | | Yes | 8 | PAD SPACE |
| utf8mb4_spanish_ci | utf8mb4 | 231 | | Yes | 8 | PAD SPACE |
| utf8mb4_sv_0900_ai_ci | utf8mb4 | 264 | | Yes | 0 | NO PAD |
| utf8mb4_sv_0900_as_cs | utf8mb4 | 287 | | Yes | 0 | NO PAD |
| utf8mb4_swedish_ci | utf8mb4 | 232 | | Yes | 8 | PAD SPACE |
| utf8mb4_tr_0900_ai_ci | utf8mb4 | 265 | | Yes | 0 | NO PAD |
| utf8mb4_tr_0900_as_cs | utf8mb4 | 288 | | Yes | 0 | NO PAD |
| utf8mb4_turkish_ci | utf8mb4 | 233 | | Yes | 8 | PAD SPACE |
| utf8mb4_unicode_520_ci | utf8mb4 | 246 | | Yes | 8 | PAD SPACE |
| utf8mb4_unicode_ci | utf8mb4 | 224 | | Yes | 8 | PAD SPACE |
| utf8mb4_vietnamese_ci | utf8mb4 | 247 | | Yes | 8 | PAD SPACE |
| utf8mb4_vi_0900_ai_ci | utf8mb4 | 277 | | Yes | 0 | NO PAD |
| utf8mb4_vi_0900_as_cs | utf8mb4 | 300 | | Yes | 0 | NO PAD |
| utf8mb4_zh_0900_as_cs | utf8mb4 | 308 | | Yes | 0 | NO PAD |
| utf8_bin | utf8 | 83 | | Yes | 1 | PAD SPACE |
| utf8_croatian_ci | utf8 | 213 | | Yes | 8 | PAD SPACE |
| utf8_czech_ci | utf8 | 202 | | Yes | 8 | PAD SPACE |
| utf8_danish_ci | utf8 | 203 | | Yes | 8 | PAD SPACE |
| utf8_esperanto_ci | utf8 | 209 | | Yes | 8 | PAD SPACE |
| utf8_estonian_ci | utf8 | 198 | | Yes | 8 | PAD SPACE |
| utf8_general_ci | utf8 | 33 | Yes | Yes | 1 | PAD SPACE |
| utf8_general_mysql500_ci | utf8 | 223 | | Yes | 1 | PAD SPACE |
| utf8_german2_ci | utf8 | 212 | | Yes | 8 | PAD SPACE |
| utf8_hungarian_ci | utf8 | 210 | | Yes | 8 | PAD SPACE |
| utf8_icelandic_ci | utf8 | 193 | | Yes | 8 | PAD SPACE |
| utf8_latvian_ci | utf8 | 194 | | Yes | 8 | PAD SPACE |
| utf8_lithuanian_ci | utf8 | 204 | | Yes | 8 | PAD SPACE |
| utf8_persian_ci | utf8 | 208 | | Yes | 8 | PAD SPACE |
| utf8_polish_ci | utf8 | 197 | | Yes | 8 | PAD SPACE |
| utf8_romanian_ci | utf8 | 195 | | Yes | 8 | PAD SPACE |
| utf8_roman_ci | utf8 | 207 | | Yes | 8 | PAD SPACE |
| utf8_sinhala_ci | utf8 | 211 | | Yes | 8 | PAD SPACE |
| utf8_slovak_ci | utf8 | 205 | | Yes | 8 | PAD SPACE |
| utf8_slovenian_ci | utf8 | 196 | | Yes | 8 | PAD SPACE |
| utf8_spanish2_ci | utf8 | 206 | | Yes | 8 | PAD SPACE |
| utf8_spanish_ci | utf8 | 199 | | Yes | 8 | PAD SPACE |
| utf8_swedish_ci | utf8 | 200 | | Yes | 8 | PAD SPACE |
| utf8_tolower_ci | utf8 | 76 | | Yes | 1 | PAD SPACE |
| utf8_turkish_ci | utf8 | 201 | | Yes | 8 | PAD SPACE |
| utf8_unicode_520_ci | utf8 | 214 | | Yes | 8 | PAD SPACE |
| utf8_unicode_ci | utf8 | 192 | | Yes | 8 | PAD SPACE |
| utf8_vietnamese_ci | utf8 | 215 | | Yes | 8 | PAD SPACE |
+----------------------------+----------+-----+---------+----------+---------+---------------+
272 rows in set (0.02 sec)

The above execution results show the proofing set name (Collation)、 Corresponding character set name (Charset)、 Proofreading set ID(Id)、 Whether it is the default proofreading set of the corresponding character set (Default)、 Whether it has been compiled (Compiled)、 Memory requirements for sorting (Sortlen) And whether you need to compare the space after the character when sorting (Pad_attribute).

among , The name of the proofreading set is given by _ It's made up of three parts :

  • It starts with the corresponding character set ;
  • In the middle is the name of the country or general;
  • It ends with cics or bin.ci Indicates case insensitive ,cs Means case sensitive ,bin Represents a binary comparison of .

such as ,gbk_chinese_ci representative gbk Character set 、 China 、 Case insensitive .

2.2、 Query metadata dictionary table

mysql> select * from information_schema.collations;
+----------------------------+--------------------+-----+------------+-------------+---------+---------------+
| COLLATION_NAME | CHARACTER_SET_NAME | ID | IS_DEFAULT | IS_COMPILED | SORTLEN | PAD_ATTRIBUTE |
+----------------------------+--------------------+-----+------------+-------------+---------+---------------+
| armscii8_general_ci | armscii8 | 32 | Yes | Yes | 1 | PAD SPACE |
...
+----------------------------+--------------------+-----+------------+-------------+---------+---------------+
272 rows in set (0.00 sec)

Reference resources :
https://dev.mysql.com/doc/refman/8.0/en/charset.html
https://zhuanlan.zhihu.com/p/147207165


Oracle MySQL The best learning roadmap (2020 The latest version )



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