When sorting data, there are various types of indexes that can be used, depending on the database system and the data characteristics. B-tree index is the most common type, organizing the data in a balanced tree structure with each node having a range of values and pointers to lower-level nodes or leaf nodes. This type of index can support sorting on one or more columns, in ascending or descending order, and can handle queries with equality, range, or prefix conditions. Another type of index is the hash index, which uses a hash function to map values to buckets containing pointers to rows with the same hash value. This type of index can only support sorting on a single column and queries with equality conditions. Lastly, there is the bitmap index which uses a bitmap or binary vector to represent existence or absence of a value in a column for each row in the table. This index can also support sorting on a single column and queries with equality or range conditions; however, it is only suitable for columns with low cardinality due to its large memory consumption.