Hierarchical queries in Oracle EBS help in understanding parent-child relationships within flex values for effective reporting.Using tables like FND_FLEX_VALUE_NORM_HIERARCHY and FND_FLEX_VALUE_CHILDREN_V aids in constructing queries for hierarchical data retrieval.Example query using FND_FLEX_VALUE_NORM_HIERARCHY showcases retrieving flex values with their hierarchy, displaying depth and paths.Alternatively, the query utilizing FND_FLEX_VALUE_CHILDREN_V simplifies hierarchy retrieval, but may not list top parents.