I'm not sure how else to post it, so here is the plan in XML format.

<?xml version="1.0" encoding="utf-16"?>

<ShowPlanXML xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" Version="1.1.1" Build="10.0.5512.0" xmlns="http://schemas.microsoft.com/sqlserver/2004/07/showplan">

<BatchSequence>

<Batch>

...

I modified the query to select just the past two (2) weeks, and it sped up significantly. I welcome any other performance enhancement suggestions, but this may have solved the...

ScottPletcher (11/19/2014)

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Probably the big thing is to reduce all the gyrations around UnitLog. Please try the query below. If you tend to restrict UnitLog rows using fldDateTime range,...

Your original code used datetime to determine the "last" row. Indeed, it went to the trouble of a separate subquery to insure that datetime was determinate instead of RCN.

You...

ScottPletcher (11/19/2014)

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Didn't see the test data when initially coding. I had to add RCN to the ORDER BY in case there are duplicate times ... although it seems odd/counterintuitive...

Here are the insert statements:

INSERT INTO dbo.UnitLog (RCN, UnitNumber, UnitStatus, fldDateTime, CCNo, CommCenter) VALUES

('1','373','10-41','2014-11-07 15:59:00.0000000','2014-000057','20'),

('2','373','10-17','2014-11-07 16:59:00.0000000','2014-000057','20'),

('3','373','10-23','2014-11-07 17:09:00.0000000','2014-000057','20'),

('4','373','LOG','2014-11-07 17:19:00.0000000','2014-000057','20'),

('5','374','10-8','2014-11-07 15:59:00.0000000','2014-000059','20'),

('6','374','10-17','2014-11-07 19:49:00.0000000','2014-000060','20'),

('7','374','10-23','2014-11-07 19:59:00.0000000','2014-000060','20'),

('8','374','10-17','2014-11-07 20:04:00.0000000','2014-000061','20'),

('9','374','10-7','2014-11-07 20:19:00.0000000','2014-000061','20'),

('10','371','10-8','2014-11-07 11:29:00.0000000','2014-000055','20'),

('11','371','10-42','2014-11-07 11:59:00.0000000','','20'),

('12','372','10-23','2014-11-07 12:59:00.0000000','2014-000056','20'),

('13','372','LOG','2014-11-07 13:59:00.0000000','2014-000056','20'),

('14','372','10-8','2014-11-07 15:59:00.0000000''2014-000056',,'20'),

('15','372','10-7','2014-11-07 15:59:00.0000000','','20')

GO

INSERT INTO...

Thanks for the reply, and I apologize, I did not understand the use of the IfCode Shortcuts before. I will try to provide the information as best as I can....