Difference of create Index by using include column or not using
问题 I Want To Create Index In SQL Server 2008 R2 in Column1 and Column2 What is the difference of below query: Not include CREATE NONCLUSTERED INDEX [IX_1] ON [dbo].[MyTable] ( [Column1] ASC, [Column2] ASC ) ON [PRIMARY] Or include: CREATE NONCLUSTERED INDEX [IX_2] ON [dbo].[MyTable] ( [Column1] ASC ) INCLUDE ([Column2]) ON [PRIMARY] 回答1: In the first one Column2 gets added to the index key. In the second one it might not (*) get added to the key in which case it will only appear in the index