See the CREATE DOMAIN statement for details.

    You cannot use the FROM path-name clause when embedding a CREATE
    DOMAIN statement in a CREATE SCHEMA statement. You can, however,
    issue a separate CREATE DOMAIN statement following the CREATE
    SCHEMA statement. You can also describe the domain directly
    within the CREATE SCHEMA statement.

    If you want to specify a collating sequence in your embedded
    CREATE DOMAIN statement, you must first specify a CREATE
    COLLATING SEQUENCE statement within the same CREATE SCHEMA
    statement.