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SQLAdvanced#indexes#performance
SQLAdvanced#indexes
Clustered vs non-clustered index?
A clustered index defines the physical order of the table rows, so there is only one per table. A non-clustered index is a separate structure holding key values plus a pointer to the row; a table can have many.
Example
-- SQL Server CREATE CLUSTERED INDEX ix_orders_id ON orders(id); CREATE NONCLUSTERED INDEX ix_orders_date ON orders(order_date);