When you have a specific SQL statement that is been running in your database (e.g., it might be part of nightly ETL flow that is used for loading your Data Warehouse), then how can you get a list of all available execution plans that the optimizer has chosen for this specific statement?
Each statement is uniquely identified by an SQL_ID and whenever the statement undergoes a hard parsing, then an execution plan is generated, which is identified uniquely by a hash value, called plan_hash_value.