MySQL - SET CHARACTER SET 語句

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MySQL 的字元集是一組在字串中允許使用的合法字元。MySQL 提供了多個字元集，您可以使用SHOW CHARACTER SET語句檢視所有可用字元集的列表。

SHOW CHARACTER SET\G;

輸出

上述 MySQL 查詢產生以下輸出：

*********** 1. row **********
          Charset: armscii8
      Description: ARMSCII-8 Armenian
Default collation: armscii8_general_ci
           Maxlen: 1
********** 2. row **********
          Charset: ascii
      Description: US ASCII
Default collation: ascii_general_ci
           Maxlen: 1
********** 3. row **********
          Charset: big5
      Description: Big5 Traditional Chinese
Default collation: big5_chinese_ci
           Maxlen: 2
********** 4. row **********
          Charset: binary
      Description: Binary pseudo charset
Default collation: binary
           Maxlen: 1
********** 5. row **********
          Charset: cp1250
      Description: Windows Central European
Default collation: cp1250_general_ci
           Maxlen: 1
********** 6. row **********
          Charset: cp1251
      Description: Windows Cyrillic
Default collation: cp1251_general_ci
           Maxlen: 1
********** 7. row **********
          Charset: cp1256
      Description: Windows Arabic
Default collation: cp1256_general_ci
           Maxlen: 1
********** 8. row **********
          Charset: cp1257
      Description: Windows Baltic
Default collation: cp1257_general_ci
           Maxlen: 1
********** 9. row **********
          Charset: cp850
      Description: DOS West European
Default collation: cp850_general_ci
           Maxlen: 1
********** 10. row **********
          Charset: cp852
      Description: DOS Central European
Default collation: cp852_general_ci
           Maxlen: 1
********** 11. row **********
          Charset: cp866
      Description: DOS Russian
Default collation: cp866_general_ci
           Maxlen: 1
********** 12. row **********
          Charset: cp932
      Description: SJIS for Windows Japanese
Default collation: cp932_japanese_ci
           Maxlen: 2
********** 13. row **********
          Charset: dec8
      Description: DEC West European
Default collation: dec8_swedish_ci
           Maxlen: 1
********** 14. row **********
          Charset: eucjpms
      Description: UJIS for Windows Japanese
Default collation: eucjpms_japanese_ci
           Maxlen: 3
********** 15. row **********
          Charset: euckr
      Description: EUC-KR Korean
Default collation: euckr_korean_ci
           Maxlen: 2
********** 16. row **********
          Charset: gb18030
      Description: China National Standard GB18030
Default collation: gb18030_chinese_ci
           Maxlen: 4
********** 17. row **********
          Charset: gb2312
      Description: GB2312 Simplified Chinese
Default collation: gb2312_chinese_ci
           Maxlen: 2
********** 18. row **********
          Charset: gbk
      Description: GBK Simplified Chinese
Default collation: gbk_chinese_ci
           Maxlen: 2
********** 19. row **********
          Charset: geostd8
      Description: GEOSTD8 Georgian
Default collation: geostd8_general_ci
           Maxlen: 1
********** 20. row **********
          Charset: greek
      Description: ISO 8859-7 Greek
Default collation: greek_general_ci
           Maxlen: 1
********** 21. row **********
          Charset: hebrew
      Description: ISO 8859-8 Hebrew
Default collation: hebrew_general_ci
           Maxlen: 1
********** 22. row **********
          Charset: hp8
      Description: HP West European
Default collation: hp8_english_ci
           Maxlen: 1
********** 23. row **********
          Charset: keybcs2
      Description: DOS Kamenicky Czech-Slovak
Default collation: keybcs2_general_ci
           Maxlen: 1
********** 24. row **********
          Charset: koi8r
      Description: KOI8-R Relcom Russian
Default collation: koi8r_general_ci
           Maxlen: 1
********** 25. row **********
          Charset: koi8u
      Description: KOI8-U Ukrainian
Default collation: koi8u_general_ci
           Maxlen: 1
********** 26. row **********
          Charset: latin1
      Description: cp1252 West European
Default collation: latin1_swedish_ci
           Maxlen: 1
********** 27. row **********
          Charset: latin2
      Description: ISO 8859-2 Central European
Default collation: latin2_general_ci
           Maxlen: 1
********** 28. row **********
          Charset: latin5
      Description: ISO 8859-9 Turkish
Default collation: latin5_turkish_ci
           Maxlen: 1
********** 29. row **********
          Charset: latin7
      Description: ISO 8859-13 Baltic
Default collation: latin7_general_ci
           Maxlen: 1
********** 30. row **********
          Charset: macce
      Description: Mac Central European
Default collation: macce_general_ci
           Maxlen: 1
********** 31. row **********
          Charset: macroman
      Description: Mac West European
Default collation: macroman_general_ci
           Maxlen: 1
********** 32. row **********
          Charset: sjis
      Description: Shift-JIS Japanese
Default collation: sjis_japanese_ci
           Maxlen: 2
********** 33. row **********
          Charset: swe7
      Description: 7bit Swedish
Default collation: swe7_swedish_ci
           Maxlen: 1
********** 34. row **********
          Charset: tis620
      Description: TIS620 Thai
Default collation: tis620_thai_ci
           Maxlen: 1
********** 35. row **********
          Charset: ucs2
      Description: UCS-2 Unicode
Default collation: ucs2_general_ci
           Maxlen: 2
********** 36. row **********
          Charset: ujis
      Description: EUC-JP Japanese
Default collation: ujis_japanese_ci
           Maxlen: 3
********** 37. row **********
          Charset: utf16
      Description: UTF-16 Unicode
Default collation: utf16_general_ci
           Maxlen: 4
********** 38. row **********
          Charset: utf16le
      Description: UTF-16LE Unicode
Default collation: utf16le_general_ci
           Maxlen: 4
********** 39. row **********
          Charset: utf32
      Description: UTF-32 Unicode
Default collation: utf32_general_ci
           Maxlen: 4
********** 40. row **********
          Charset: utf8mb3
      Description: UTF-8 Unicode
Default collation: utf8mb3_general_ci
           Maxlen: 3
********** 41. row **********
          Charset: utf8mb4
      Description: UTF-8 Unicode
Default collation: utf8mb4_0900_ai_ci
           Maxlen: 4

您可以使用以下查詢獲取預設字元集的名稱：

SELECT default_character_set_name FROM information_schema.SCHEMATA S 
WHERE schema_name = "test";

輸出

執行上述 MySQL 查詢後，它將生成如下所示的輸出：

DEFAULT_CHARACTER_SET_NAME
utf8mb4

SET CHARACTER SET 語句

MySQL 的 SET CHARACTER SET 語句用於為字元集屬性賦值。它使用指定的對映集對映伺服器和當前客戶端之間的所有字串。此語句更改 character_set_client 和 character_set_results 變數的值。

語法

以下是 MySQL SET CHARACTER SET 語句的語法：

SET {CHARACTER SET | CHARSET}
   {'charset_name' | DEFAULT}

其中，'charset_name' 是字元集的名稱。

示例

以下查詢將字元集設定為 macroman：

SET CHARACTER SET macroman;

驗證

您可以使用 show variables like 語句驗證 character_set_client 和 character_set_results 變數的當前值，如下所示：

show variables like "character_set_client";

輸出

上述查詢產生以下輸出：

Variable_name	Value
character_set_client	macroman

show variables like "character_set_results";

輸出

以下是上述 MySQL 查詢的輸出：

Variable_name	Value
character_set_results	macroman

DEFAULT 值

您可以使用 DEFAULT 作為值將字元集對映設定為資料庫的預設值，如下所示：

SET CHARACTER SET DEFAULT;

由於預設字元集是 utf8mb4，因此 character_set_client 和 character_set_results 變數的值將設定為它。您可以驗證這些值，如下所示：

show variables like "character_set_results";

輸出

執行上述查詢後，它將產生以下輸出：

Variable_name	Value
character_set_results	utf8mb4

show variables like "character_set_client";

輸出

上述 MySQL 查詢將生成如下所示的輸出：

Variable_name	Value
character_set_client	utf8mb4

SET CHARSET 語句

您也可以使用 CHARSET 關鍵字代替 CHARACTER SET，如下所示：

SET CHARSET latin7;

驗證

讓我們使用 show variables like 語句驗證 character_set_client 或 character_set_results 變數的當前值，如下所示：

show variables like "character_set_client";

輸出

執行上述查詢後，它將產生以下輸出：

Variable_name	Value
character_set_client	latin7