SQL duplicates - Distinct fails when using ROW_NUMBER()

Posted on 2011-10-31
Medium Priority
Last Modified: 2012-05-12
This example will show the problem.
Create the 2 tables, run the insert then the problem query to see it.

"Should" return one distinct row.
Looking for a way around it.
Looks like distinct is applied after the ROW_NUMBERS() are
made, so, distinct fails because of the row numbers.

How can you get around this?
We need both the row_number() and distinct

CREATE TABLE [dbo].[Table_1](
      [id] [int] IDENTITY(1,1) NOT NULL,
      [description] [nchar](10) NULL

CREATE TABLE [dbo].[Table_2](
      [id] [int] IDENTITY(1,1) NOT NULL,
      [Table_1_ID] [int] NULL,
      [description] [nchar](10) NULL

insert into table_1(description)values('data1')
insert into table_1(description)values('data2')

insert into table_2([Table_1_ID],description)values(1,'A')
insert into table_2([Table_1_ID],description)values(1,'B')
insert into table_2([Table_1_ID],description)values(1,'C')

Run this query, which should return the one row from

select distinct Table_1.description
,ROW_NUMBER() over (ORDER BY Table_1.description) as rowid
from Table_1  join Table_2 on Table_2.table_1_id = Table_1.id
where Table_1.description= 'data1'

Question by:awalkinthepark
LVL 39

Accepted Solution

appari earned 1000 total points
ID: 37060224
if you need both distinct and row_number use it like this

Select *, ROW_NUMBER() over (ORDER BY description) as rowid
select distinct Table_1.description
from Table_1  join Table_2 on Table_2.table_1_id = Table_1.id
where Table_1.description= 'data1') as A
LVL 143

Assisted Solution

by:Guy Hengel [angelIII / a3]
Guy Hengel [angelIII / a3] earned 1000 total points
ID: 37061876

Author Closing Comment

ID: 37067152
Excellent article from angelIl
Obviously more all encompassing.
appari - got there first and is directly to the point.
Wish I could award 500 each.
Thanks guys

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