Final answer:
A temporary table is used to store data for the duration of a single query or session, and is invalid once the query completes or the session ends.
Step-by-step explanation:
A temporary table is not valid after the query is run - it is only valid for one query. Temporary tables are used to store temporary data that is only needed for the duration of a single query or session. Once the query completes or the session ends, the temporary table is automatically dropped and its data is lost. They are particularly useful in complex operations where intermediate results need to be stored temporarily or when dealing with large data sets that need to be manipulated in multiple steps.