Collation Rules

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

Differences in collation rules:

In GaussDB, 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 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.
In GaussDB, a character set must be the same as the database-level character set, which is also the prerequisite of specifying collation rules (except binary). 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'.