NOEXPAND is a TSQL query hint, which we use with indexed views in certain scenarios.
NOEXPAND
Indexed views (or materialized views) are the ones which store underlying data in the database, where normal views generate data for the underlying query on run time.
However, even though indexed view store actual data for the view, there is a change SQL server still use the underlying query directly to generate the data when view is used in a query.
Under some circumstances, this can cause poor performances. So to improve performances, you can force SQL server to use underlying data on the query by using this query hint.
