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MySQLORD()函数使用实例介绍

时间:2021-07-01 10:21:17 帮助过:49人阅读

ORD() 函数返回字符串第一个字符的ASCII 值。

语法: ORD(string)

举一些简单的例子:

  1. <code class="language-sql">mysql> SELECT ORD('i');
  2. +----------+
  3. | ORD('i') |
  4. +----------+
  5. | 105 |
  6. +----------+
  7. 1 row in set</code>

或者:

  1. <code class="language-sql">mysql> SELECT ORD('NowaMagic');
  2. +------------------+
  3. | ORD('NowaMagic') |
  4. +------------------+
  5. | 78 |
  6. +------------------+
  7. 1 row in set</code>

如果汉字又如何呢?

  1. <code class="language-sql">mysql> SELECT ORD('简明现代魔法');
  2. +---------------------+
  3. | ORD('简明现代魔法') |
  4. +---------------------+
  5. | 15183488 |
  6. +---------------------+
  7. 1 row in set
  8. mysql> SELECT ORD('简');
  9. +-----------+
  10. | ORD('简') |
  11. +-----------+
  12. | 15183488 |
  13. +-----------+
  14. 1 row in set</code>

为什么会有 8 位数那么长呢?原因是数据库使用的字符集问题,此处的数据库使用的是 UTF-8,16位表示一个符号。顺便贴一下SQL的执行语句:

  1. <code class="language-sql">mysql> SHOW CHARACTER SET;
  2. +----------+-----------------------------+---------------------+--------+
  3. | Charset | Description | Default collation | Maxlen |
  4. +----------+-----------------------------+---------------------+--------+
  5. | big5 | Big5 Traditional Chinese | big5_chinese_ci | 2 |
  6. | dec8 | DEC West European | dec8_swedish_ci | 1 |
  7. | cp850 | DOS West European | cp850_general_ci | 1 |
  8. | hp8 | HP West European | hp8_english_ci | 1 |
  9. | koi8r | KOI8-R Relcom Russian | koi8r_general_ci | 1 |
  10. | latin1 | cp1252 West European | latin1_swedish_ci | 1 |
  11. | latin2 | ISO 8859-2 Central European | latin2_general_ci | 1 |
  12. | swe7 | 7bit Swedish | swe7_swedish_ci | 1 |
  13. | ascii | US ASCII | ascii_general_ci | 1 |
  14. | ujis | EUC-JP Japanese | ujis_japanese_ci | 3 |
  15. | sjis | Shift-JIS Japanese | sjis_japanese_ci | 2 |
  16. | hebrew | ISO 8859-8 Hebrew | hebrew_general_ci | 1 |
  17. | tis620 | TIS620 Thai | tis620_thai_ci | 1 |
  18. | euckr | EUC-KR Korean | euckr_korean_ci | 2 |
  19. | koi8u | KOI8-U Ukrainian | koi8u_general_ci | 1 |
  20. | gb2312 | GB2312 Simplified Chinese | gb2312_chinese_ci | 2 |
  21. | greek | ISO 8859-7 Greek | greek_general_ci | 1 |
  22. | cp1250 | Windows Central European | cp1250_general_ci | 1 |
  23. | gbk | GBK Simplified Chinese | gbk_chinese_ci | 2 |
  24. | latin5 | ISO 8859-9 Turkish | latin5_turkish_ci | 1 |
  25. | armscii8 | ARMSCII-8 Armenian | armscii8_general_ci | 1 |
  26. | utf8 | UTF-8 Unicode | utf8_general_ci | 3 |
  27. | ucs2 | UCS-2 Unicode | ucs2_general_ci | 2 |
  28. | cp866 | DOS Russian | cp866_general_ci | 1 |
  29. | keybcs2 | DOS Kamenicky Czech-Slovak | keybcs2_general_ci | 1 |
  30. | macce | Mac Central European | macce_general_ci | 1 |
  31. | macroman | Mac West European | macroman_general_ci | 1 |
  32. | cp852 | DOS Central European | cp852_general_ci | 1 |
  33. | latin7 | ISO 8859-13 Baltic | latin7_general_ci | 1 |
  34. | utf8mb4 | UTF-8 Unicode | utf8mb4_general_ci | 4 |
  35. | cp1251 | Windows Cyrillic | cp1251_general_ci | 1 |
  36. | utf16 | UTF-16 Unicode | utf16_general_ci | 4 |
  37. | cp1256 | Windows Arabic | cp1256_general_ci | 1 |
  38. | cp1257 | Windows Baltic | cp1257_general_ci | 1 |
  39. | utf32 | UTF-32 Unicode | utf32_general_ci | 4 |
  40. | binary | Binary pseudo charset | binary | 1 |
  41. | geostd8 | GEOSTD8 Georgian | geostd8_general_ci | 1 |
  42. | cp932 | SJIS for Windows Japanese | cp932_japanese_ci | 2 |
  43. | eucjpms | UJIS for Windows Japanese | eucjpms_japanese_ci | 3 |
  44. +----------+-----------------------------+---------------------+--------+
  45. 39 rows in set</code>

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