NONCLUSTERED INDEX VS CLUSTERED INDEX

Same:

1. Both clustered and nonclustered indexes can be made up of more than one column.

2. Both clustered indexes, and nonclustered indexes take up additional disk space.

3. Adding indexes (both clustered and nonclusterd) will increase the amount of time that your INSERT, UPDATE and DELETE statement take, as the data has to be updated in the table as well as in each index.

Difference:

1. SQL Server only supports a single clustered index per each database table, but up to 999 nonclustered indexes.