SHOW COLLATION

SHOW COLLATION 语句用于提供一个静态的排序规则列表,确保与 MySQL 客户端库的兼容性。

语法图

ShowCollationStmt
SHOWCOLLATIONShowLikeOrWhere
ShowLikeOrWhere
LIKESimpleExprWHEREExpression

示例

若未开启新排序规则框架,仅展示二进制排序规则:

SHOW COLLATION;
+-------------+---------+------+---------+----------+---------+ | Collation | Charset | Id | Default | Compiled | Sortlen | +-------------+---------+------+---------+----------+---------+ | utf8mb4_bin | utf8mb4 | 46 | Yes | Yes | 1 | | latin1_bin | latin1 | 47 | Yes | Yes | 1 | | binary | binary | 63 | Yes | Yes | 1 | | ascii_bin | ascii | 65 | Yes | Yes | 1 | | utf8_bin | utf8 | 83 | Yes | Yes | 1 | +-------------+---------+------+---------+----------+---------+ 5 rows in set (0.02 sec)

若开启了新排序规则框架,则在二进制排序规则之外,额外支持 utf8_general_ciutf8mb4_general_ci 两种大小写和口音不敏感的排序规则:

SHOW COLLATION;
+--------------------+---------+------+---------+----------+---------+ | Collation | Charset | Id | Default | Compiled | Sortlen | +--------------------+---------+------+---------+----------+---------+ | ascii_bin | ascii | 65 | Yes | Yes | 1 | | binary | binary | 63 | Yes | Yes | 1 | | gbk_bin | gbk | 87 | | Yes | 1 | | gbk_chinese_ci | gbk | 28 | Yes | Yes | 1 | | latin1_bin | latin1 | 47 | Yes | Yes | 1 | | utf8_bin | utf8 | 83 | Yes | Yes | 1 | | utf8_general_ci | utf8 | 33 | | Yes | 1 | | utf8_unicode_ci | utf8 | 192 | | Yes | 1 | | utf8mb4_bin | utf8mb4 | 46 | Yes | Yes | 1 | | utf8mb4_general_ci | utf8mb4 | 45 | | Yes | 1 | | utf8mb4_unicode_ci | utf8mb4 | 224 | | Yes | 1 | +--------------------+---------+------+---------+----------+---------+ 11 rows in set (0.001 sec)

要过滤字符集,可以添加 WHERE 子句。

SHOW COLLATION WHERE Charset="utf8mb4";
+--------------------+---------+-----+---------+----------+---------+ | Collation | Charset | Id | Default | Compiled | Sortlen | +--------------------+---------+-----+---------+----------+---------+ | utf8mb4_0900_ai_ci | utf8mb4 | 255 | | Yes | 1 | | utf8mb4_0900_bin | utf8mb4 | 309 | | Yes | 1 | | utf8mb4_bin | utf8mb4 | 46 | Yes | Yes | 1 | | utf8mb4_general_ci | utf8mb4 | 45 | | Yes | 1 | | utf8mb4_unicode_ci | utf8mb4 | 224 | | Yes | 1 | +--------------------+---------+-----+---------+----------+---------+ 5 rows in set (0.00 sec)

MySQL 兼容性

SHOW COLLATION 语句功能与 MySQL 完全兼容。注意,TiDB 中字符集的默认排序规则与 MySQL 有所不同,具体可参考与 MySQL 兼容性对比。如发现任何其他兼容性差异,请尝试 TiDB 支持资源

另请参阅

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