Is it possible to use multiple database index structures simultaneously in a single SQL query?

Yes, a single SQL query can use multiple index structures if the query involves several columns for which indexes are created. Modern DBMSs can combine indexes (e.g., through index merging or bitmap indexes) to optimize query execution.

For example, if there are indexes on columns A and B, and the query filters on both, the DBMS can use both indexes to speed up the selection. However, the efficiency depends on the specific DBMS and data structure.