NONCLUSTERED INDEX

Index that does not affect the order of then records within the table.

You can have multiple index per table.

This works by creating a new “table” that is ordered by the ColName1.

Then it searches for the records to select by the clustered index.

CREATE NONCLUSTERED INDEX ix_SchemaName_TableName_ColName -- NONCLUSTERED can be omitted
	ON SchemaName.TableName (ColName)
	
CREATE INDEX ix_SchemaName_TableName_ColName1_ColName2
	ON SchemaName.TableName (ColName1, ColName2)

Include

This allows you to include columns on the index table, so that the DB does not have to find the ColName, then search for the nonclustered index on the main table. Instead it just searches for the ColName on the index, and grabs the other data.

CREATE INDEX ix_SchemaName_TableName_ColName1
	ON SchemaName.TableName (ColName1) INCLUDE (OtherColumn)