You can create Indexes with 16 KEY COLUMNS in both Clustered and NonClustered Indexes. You can also INCLUDE 1023 NON KEY COLUMNS in NonClustered Index. Create NonClustered Index Ix_NC_Test On Test(Col1) Include(Col2,Col3) Col1 is Key Column(Upto 16) and Col2 and 3 are NonKey Columns(Upto 1023)

In SQL Server, you can include non key columns in a non-clustered index to avoid the limitation of a maximum of 16 key columns. For more information, see Create Indexes with Included Columns. The maximum number of bytes in an index key is 900.

Object SQL Server 7.0 SQL Server 2000 SQL Server 2005 SQL Server 2008 Clustered Index 1 1 1 1 Non-clustered Index 249 249 249 999