Avoid using WHERE
and ORDER BY
clauses in hierachical queries, because they run after the hierarchical processing. Here I think you should use START WITH component_label = 'Sample'
.
SELECT level, components.component_id, components.component_label, component_color.component_color
FROM compenents JOIN component_color ON components.component = component_color.component
START WITH components.component_label = 'Sample'
CONNECT BY PRIOR components.component_id = components.component_parent_id