ClickHouse/tests/integration/test_user_zero_database_access/configs/users.xml

<clickhouse>
    <profiles>
        <default>
        </default>
    </profiles>

    <users>
        <default>
            <password></password>
            <networks incl="networks" replace="replace">
                <ip>::/0</ip>
            </networks>
            <profile>default</profile>
            <quota>default</quota>
        </default>

        <no_access>
            <password></password>
            <networks incl="networks" replace="replace">
                <ip>::/0</ip>
            </networks>
            <profile>default</profile>
            <quota>default</quota>
            <allow_databases></allow_databases>
        </no_access>

        <has_access>
            <password></password>
            <networks incl="networks" replace="replace">
                <ip>::/0</ip>
            </networks>
            <profile>default</profile>
            <quota>default</quota>
            <allow_databases>
                <database>test</database>
                <database>db1</database>
            </allow_databases>
        </has_access>

        <env_user_with_password>
            <password>clickhouse</password>
            <networks incl="networks" replace="replace">
                <ip>::/0</ip>
            </networks>
            <profile>default</profile>
            <quota>default</quota>
        </env_user_with_password>

        <env_user_not_with_password>
            <password></password>
            <networks incl="networks" replace="replace">
                <ip>::/0</ip>
            </networks>
            <profile>default</profile>
            <quota>default</quota>
        </env_user_not_with_password>        
    </users>

    <quotas>
        <default>
        </default>
    </quotas>
</clickhouse>