CREATE TABLE dbo.Tmp_bob
	(
	pkColA varchar(15) NOT NULL,
	otherCol float(53) NULL,
	pkColB varchar(3) NOT NULL,
	otherCols datetime NULL
	)
GO

ALTER TABLE dbo.Tmp_bob ADD CONSTRAINT
	PK_Tmp_bob PRIMARY KEY CLUSTERED
	(
	pkColA,
	pkColB
	) WITH( STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO

SELECT pkColA FROM Tmp_bob
-- It scans the clustered primay key.

CREATE NONCLUSTERED INDEX IX_Tmp_bob_pkColA ON Tmp_bob(pkColA) WITH  PAD_INDEX, FILLFACTOR = 80
CREATE NONCLUSTERED INDEX IX_Tmp_bob_pkColB ON Tmp_bob(pkColB) WITH  PAD_INDEX, FILLFACTOR = 80
SELECT pkColA FROM Tmp_bob
-- It scans IX_Tmp_bob_pkColB

DROP INDEX Tmp_bob.IX_Tmp_bob_pkColA
DROP INDEX Tmp_bob.IX_Tmp_bob_pkColB
CREATE NONCLUSTERED INDEX IX_Tmp_bob_pkColB ON Tmp_bob(pkColB) WITH  PAD_INDEX, FILLFACTOR = 80
CREATE NONCLUSTERED INDEX IX_Tmp_bob_pkColA ON Tmp_bob(pkColA) WITH  PAD_INDEX, FILLFACTOR = 80
SELECT pkColA FROM Tmp_bob
-- It scans IX_Tmp_bob_pkColA

We walk in the dark places no others will enter
We stand on the bridge and no one may pass

We walk in the dark places no others will enter
We stand on the bridge and no one may pass

We walk in the dark places no others will enter
We stand on the bridge and no one may pass