CREATE TABLE catalog_structure (catalog_level_number NUMBER, catalog_id NUMBER, catalog_level_name CLOB)
CREATE TABLE catalogs (catalog_id NUMBER, catalog_name CLOB, catalog_publisher CLOB, date_of_publication TIME, date_of_latest_revision TIME)
CREATE TABLE catalog_contents (catalog_entry_id NUMBER, catalog_level_number NUMBER, parent_entry_id NUMBER, previous_entry_id NUMBER, next_entry_id NUMBER, catalog_entry_name CLOB, product_stock_number CLOB, price_in_dollars NUMBER, price_in_euros NUMBER, price_in_pounds NUMBER, capacity CLOB, length CLOB, height CLOB, width CLOB)
CREATE TABLE catalog_contents_additional_attributes (catalog_entry_id NUMBER, catalog_level_number NUMBER, attribute_id NUMBER, attribute_value CLOB)
CREATE TABLE attribute_definitions (attribute_id NUMBER, attribute_name CLOB, attribute_data_type CLOB)

On which days more than one revisions were made on catalogs.
SELECT date_of_latest_revision FROM catalogs GROUP BY date_of_latest_revision HAVING COUNT(*) > 1
SELECT "date_of_latest_revision" FROM "catalogs" GROUP BY "date_of_latest_revision" HAVING COUNT(*) > 1