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mysql encoding

錢諍諍2年前15瀏覽0評論

MySQL是一種常用的關系型數據庫系統,它支持多種編碼。編碼是用于表示文本字符集的方式,MySQL中的編碼稱為字符集(charset),在不同的字符集下,相同的字符可能會有不同的編碼。

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   | ISO 8859-1 Latin 1           | latin1_swedish_ci   |      1 |
| latin2   | ISO 8859-2 Central European | latin2_general_ci   |      1 |
| swe7     | 7bit Swedish                | swe7_swedish_ci     |      1 |
| utf8     | UTF-8 Unicode               | utf8_general_ci     |      3 |
| utf8mb4  | UTF-8 Unicode               | utf8mb4_general_ci  |      4 |
| ucs2     | UCS-2 Unicode               | ucs2_general_ci     |      2 |
| 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 |
+----------+-----------------------------+---------------------+--------+

MySQL中最常用的字符集是UTF-8,因為它可以支持眾多的語言,包括中文、韓文、日文等等。在使用UTF-8字符集時,需要注意在創建表和插入數據時,要保證字符集一致,否則數據可能無法正確顯示。

mysql>CREATE TABLE `test` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(20) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8;
mysql>INSERT INTO `test` (`id`, `name`) VALUES (1, '測試'), (2, '中文'), (3, 'MySQL');
mysql>SELECT * FROM `test`;
+----+--------+
| id | name   |
+----+--------+
|  1 | 測試   |
|  2 | 中文   |
|  3 | MySQL |
+----+--------+

在處理字符集時,還需要注意一些細節問題。例如,在查詢過程中,字符串比較可能會受到字符集和排序規則的影響。如果需要進行精確匹配或排序,需要使用相應的字符集和排序規則。