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Help Center/ GaussDB/ MySQL Compatibility(Centralized)/ MySQL Compatibility in M-Compatible Mode/ Collation Rules

Collation Rules

Updated on 2024-12-06 GMT+08:00

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GaussDB allows you to specify the following collation rules for schemas, tables, or columns.

NOTE:

Differences in collation rules:

Currently, only the character string type and some binary types support the specified collation rules. You can check whether the typcollation attribute of a type in the pg_type system catalog is not 0 to determine whether the type supports the collation. The collation can be specified for all types in MySQL. However, collation rules are meaningless except those for character strings and binary types.
The current collation rules (except binary) can be specified only when the corresponding character set is the same as the database-level character set. In GaussDB, the character set must be the same as the database character set, and multiple character sets cannot be used together in a table.
The default collation of the utf8mb4 character set is utf8mb4_general_ci, which is the same as that in MySQL 5.7.
To use the latin1 collation, you need to set the compatibility parameter m_format_dev_version to 's2'.

**Table 1** Collation rules
No.	MySQL	GaussDB
1	utf8mb4_general_ci	Supported
2	utf8mb4_unicode_ci	Supported
3	utf8mb4_bin	Supported
4	gbk_chinese_ci	Supported
5	gbk_bin	Supported
6	gb18030_chinese_ci	Supported
7	gb18030_bin	Supported
8	binary	Supported
9	utf8mb4_0900_ai_ci	Supported
10	utf8_general_ci	Supported
11	utf8_bin	Supported
12	utf8_unicode_ci	Supported.
13	latin1_swedish_ci	Supported.
14	latin1_bin	Supported.

Parent topic: MySQL Compatibility in M-Compatible Mode

Previous topic: Character Sets

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