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MS SQL order by with "over" statement and row_number()

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Last Modified: 2016-10-11
I have a query I use frequently that someone helped me write several years ago, which I often create variations on. I thought I understood exactly what it does, but I am finding a discrepancy with the "order by" that I don't understand.

This query does what I want, which is simply an alphabetical sort on the "description" column:

select distinct
	description
from
	(select row_number() over (order by description) as rownum, description
		from tbl_product
		where (itemid='LUGS & H-TAPS : YAV2CLTC10FX' or itemid='LUGS & H-TAPS : YAV2CL2TC14E2FX')) as qryresults

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RESULT:

description
"LUG COMPRESSION # 2 AWG FLEX 1 HOLE #10 STUD STANDARD BARREL 0.68"" TONGUE WIDTH BROWN W/ INSP WNDW BURNDY"
"LUG COMPRESSION # 2 AWG FLEX 2 HOLE 1/4"" STUD 3/4"" CENTER STANDARD BARREL 0.68"" TONGUE WIDTH BROWN W/ INSP WNDW BURNDY"

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This query returns the same two results, but the "order by" is backwards:

select distinct
	itemid, description
from
	(select row_number() over (order by description) as rownum, itemid, description
		from tbl_product
		where (itemid='LUGS & H-TAPS : YAV2CLTC10FX' or itemid='LUGS & H-TAPS : YAV2CL2TC14E2FX')) as qryresults

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RESULT:

itemid 	description
LUGS & H-TAPS : YAV2CL2TC14E2FX	"LUG COMPRESSION # 2 AWG FLEX 2 HOLE 1/4"" STUD 3/4"" CENTER STANDARD BARREL 0.68"" TONGUE WIDTH BROWN W/ INSP WNDW BURNDY"
LUGS & H-TAPS : YAV2CLTC10FX	"LUG COMPRESSION # 2 AWG FLEX 1 HOLE #10 STUD STANDARD BARREL 0.68"" TONGUE WIDTH BROWN W/ INSP WNDW BURNDY"

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The only difference between the two is the "itemid" column present in the "select" clause (twice). I'm not understanding why selecting that column should cause the sorting to be backwards.

Thank you!
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