Question

I’d like to get back only one row per ID, even if there are multiple rows associated with an ID.

The scenario is that the data reflects a site selling land / properties, and that for each listing, there may be multiple images associated with each ID. I need only one.

Thank You.

As requested, sample data:

RowNumber   ID  UserID  CountryID   tbl_detailsID   Name    Description Price   AddressLine1    AddressLine2    City    State   Zip AddressGPS  Space   Amenities   Policies    URL DateEntered DateExpires NumViews    IsCompanyProperty   EnforceMinStay  IsOtherSite rate_Avg    isFeatured  DayPrice    ImageURL    Name    check_in    check_out   currency    bathroom_count  pet unit_size   elder   handicap    occupancy   bedroom_count   LinkURL smoking unit_size_Units property_Type   children    Minimum_stay    Minimum_stay_Unit   CountryName
2   247586  1   1   161398  Beautiful Oceanfront Home in Cambria California Located on the Central Coast of California 10 minutes from Hearst Castle.
Phone 1: Toll Free [phone]
Phone 2: [phone] (California, USA)
direct email contact: debbie (@) maisonsdecambria.com

Leopold Cove" is a beautiful Oceanfront Home located on the Central Coast of California. It has fabulous ocean views and access to the water from a private stairway. The living area has large plate glass windows that feature 180 degree views of the Pacific Ocean. A comfortable platform style bed & a warm, cozy fireplace are also located in the living area so you can relax for hours, or even days, enjoying the beauty that surrounds you. There is a full kitchen & a separate bedroom with 2 twin beds. The property also has a picnic area & places to sit, perhaps with a good book & a glass of wine while you watch the sunset. If you are a nature lover, you will enjoy the otters, seals & birdlife that we are privileged to have so close to us. During the gray whale migration times, this is a p     2183 Sherwood Drive     Cambria California  93428   35.544712|-121.095444               http://www.flipkey.com/cambria-vacation-rentals/p202618/    2012-10-01 10:52:00 2012-10-15 10:52:00 0   0   0   703 5.0 0   NULL    http://images1.flipkey.com/img/photos/302459/243298/large_302459-243298-007-1346943508.jpg  Beautiful Oceanfront Home in Cambria California         USD 1   Ask 0   Ask Ask 4   1   http://www.flipkey.com/cambria-vacation-rentals/p202618/    Ask     House   Ask 0   NULL    United States
3   247586  1   1   161398  Beautiful Oceanfront Home in Cambria California Located on the Central Coast of California 10 minutes from Hearst Castle.
Phone 1: Toll Free [phone]
Phone 2: [phone] (California, USA)
direct email contact: debbie (@) maisonsdecambria.com

Leopold Cove" is a beautiful Oceanfront Home located on the Central Coast of California. It has fabulous ocean views and access to the water from a private stairway. The living area has large plate glass windows that feature 180 degree views of the Pacific Ocean. A comfortable platform style bed & a warm, cozy fireplace are also located in the living area so you can relax for hours, or even days, enjoying the beauty that surrounds you. There is a full kitchen & a separate bedroom with 2 twin beds. The property also has a picnic area & places to sit, perhaps with a good book & a glass of wine while you watch the sunset. If you are a nature lover, you will enjoy the otters, seals & birdlife that we are privileged to have so close to us. During the gray whale migration times, this is a p     2183 Sherwood Drive     Cambria California  93428   35.544712|-121.095444               http://www.flipkey.com/cambria-vacation-rentals/p202618/    2012-10-01 10:52:00 2012-10-15 10:52:00 0   0   0   703 5.0 0   NULL    http://images1.flipkey.com/img/photos/302459/243298/large_302459-243298-006-1346943508.jpg  Beautiful Oceanfront Home in Cambria California         USD 1   Ask 0   Ask Ask 4   1   http://www.flipkey.com/cambria-vacation-rentals/p202618/    Ask     House   Ask 0   NULL    United States
4   247586  1   1   161398  Beautiful Oceanfront Home in Cambria California Located on the Central Coast of California 10 minutes from Hearst Castle.
Phone 1: Toll Free [phone]
Phone 2: [phone] (California, USA)
direct email contact: debbie (@) maisonsdecambria.com

Leopold Cove" is a beautiful Oceanfront Home located on the Central Coast of California. It has fabulous ocean views and access to the water from a private stairway. The living area has large plate glass windows that feature 180 degree views of the Pacific Ocean. A comfortable platform style bed & a warm, cozy fireplace are also located in the living area so you can relax for hours, or even days, enjoying the beauty that surrounds you. There is a full kitchen & a separate bedroom with 2 twin beds. The property also has a picnic area & places to sit, perhaps with a good book & a glass of wine while you watch the sunset. If you are a nature lover, you will enjoy the otters, seals & birdlife that we are privileged to have so close to us. During the gray whale migration times, this is a p     2183 Sherwood Drive     Cambria California  93428   35.544712|-121.095444               http://www.flipkey.com/cambria-vacation-rentals/p202618/    2012-10-01 10:52:00 2012-10-15 10:52:00 0   0   0   703 5.0 0   NULL    http://images1.flipkey.com/img/photos/302459/243298/large_302459-243298-005-1346943508.jpg  Beautiful Oceanfront Home in Cambria California         USD 1   Ask 0   Ask Ask 4   1   http://www.flipkey.com/cambria-vacation-rentals/p202618/    Ask     House   Ask 0   NULL    United States
5   247586  1   1   161398  Beautiful Oceanfront Home in Cambria California Located on the Central Coast of California 10 minutes from Hearst Castle.
Phone 1: Toll Free [phone]
Phone 2: [phone] (California, USA)
direct email contact: debbie (@) maisonsdecambria.com

Leopold Cove" is a beautiful Oceanfront Home located on the Central Coast of California. It has fabulous ocean views and access to the water from a private stairway. The living area has large plate glass windows that feature 180 degree views of the Pacific Ocean. A comfortable platform style bed & a warm, cozy fireplace are also located in the living area so you can relax for hours, or even days, enjoying the beauty that surrounds you. There is a full kitchen & a separate bedroom with 2 twin beds. The property also has a picnic area & places to sit, perhaps with a good book & a glass of wine while you watch the sunset. If you are a nature lover, you will enjoy the otters, seals & birdlife that we are privileged to have so close to us. During the gray whale migration times, this is a p     2183 Sherwood Drive     Cambria California  93428   35.544712|-121.095444               http://www.flipkey.com/cambria-vacation-rentals/p202618/    2012-10-01 10:52:00 2012-10-15 10:52:00 0   0   0   703 5.0 0   NULL    http://images1.flipkey.com/img/photos/302459/243298/large_302459-243298-004-1346943508.jpg  Beautiful Oceanfront Home in Cambria California         USD 1   Ask 0   Ask Ask 4   1   http://www.flipkey.com/cambria-vacation-rentals/p202618/    Ask     House   Ask 0   NULL    United States
6   247586  1   1   161398  Beautiful Oceanfront Home in Cambria California Located on the Central Coast of California 10 minutes from Hearst Castle.
Phone 1: Toll Free [phone]
Phone 2: [phone] (California, USA)
direct email contact: debbie (@) maisonsdecambria.com

Leopold Cove" is a beautiful Oceanfront Home located on the Central Coast of California. It has fabulous ocean views and access to the water from a private stairway. The living area has large plate glass windows that feature 180 degree views of the Pacific Ocean. A comfortable platform style bed & a warm, cozy fireplace are also located in the living area so you can relax for hours, or even days, enjoying the beauty that surrounds you. There is a full kitchen & a separate bedroom with 2 twin beds. The property also has a picnic area & places to sit, perhaps with a good book & a glass of wine while you watch the sunset. If you are a nature lover, you will enjoy the otters, seals & birdlife that we are privileged to have so close to us. During the gray whale migration times, this is a p     2183 Sherwood Drive     Cambria California  93428   35.544712|-121.095444               http://www.flipkey.com/cambria-vacation-rentals/p202618/    2012-10-01 10:52:00 2012-10-15 10:52:00 0   0   0   703 5.0 0   NULL    http://images1.flipkey.com/img/photos/302459/243298/large_302459-243298-003-1346943508.jpg  Beautiful Oceanfront Home in Cambria California         USD 1   Ask 0   Ask Ask 4   1   http://www.flipkey.com/cambria-vacation-rentals/p202618/    Ask     House   Ask 0   NULL    United States
7   247586  1   1   161398  Beautiful Oceanfront Home in Cambria California Located on the Central Coast of California 10 minutes from Hearst Castle.
Phone 1: Toll Free [phone]
Phone 2: [phone] (California, USA)
direct email contact: debbie (@) maisonsdecambria.com

Leopold Cove" is a beautiful Oceanfront Home located on the Central Coast of California. It has fabulous ocean views and access to the water from a private stairway. The living area has large plate glass windows that feature 180 degree views of the Pacific Ocean. A comfortable platform style bed & a warm, cozy fireplace are also located in the living area so you can relax for hours, or even days, enjoying the beauty that surrounds you. There is a full kitchen & a separate bedroom with 2 twin beds. The property also has a picnic area & places to sit, perhaps with a good book & a glass of wine while you watch the sunset. If you are a nature lover, you will enjoy the otters, seals & birdlife that we are privileged to have so close to us. During the gray whale migration times, this is a p     2183 Sherwood Drive     Cambria California  93428   35.544712|-121.095444               http://www.flipkey.com/cambria-vacation-rentals/p202618/    2012-10-01 10:52:00 2012-10-15 10:52:00 0   0   0   703 5.0 0   NULL    http://images1.flipkey.com/img/photos/302459/243298/large_302459-243298-002-1346943508.jpg  Beautiful Oceanfront Home in Cambria California         USD 1   Ask 0   Ask Ask 4   1   http://www.flipkey.com/cambria-vacation-rentals/p202618/    Ask     House   Ask 0   NULL    United States
8   247586  1   1   161398  Beautiful Oceanfront Home in Cambria California Located on the Central Coast of California 10 minutes from Hearst Castle.
Phone 1: Toll Free [phone]
Phone 2: [phone] (California, USA)
direct email contact: debbie (@) maisonsdecambria.com

Leopold Cove" is a beautiful Oceanfront Home located on the Central Coast of California. It has fabulous ocean views and access to the water from a private stairway. The living area has large plate glass windows that feature 180 degree views of the Pacific Ocean. A comfortable platform style bed & a warm, cozy fireplace are also located in the living area so you can relax for hours, or even days, enjoying the beauty that surrounds you. There is a full kitchen & a separate bedroom with 2 twin beds. The property also has a picnic area & places to sit, perhaps with a good book & a glass of wine while you watch the sunset. If you are a nature lover, you will enjoy the otters, seals & birdlife that we are privileged to have so close to us. During the gray whale migration times, this is a p     2183 Sherwood Drive     Cambria California  93428   35.544712|-121.095444               http://www.flipkey.com/cambria-vacation-rentals/p202618/    2012-10-01 10:52:00 2012-10-15 10:52:00 0   0   0   703 5.0 0   NULL    http://images1.flipkey.com/img/photos/302459/243298/large_302459-243298-001-1346943508.jpg  Beautiful Oceanfront Home in Cambria California         USD 1   Ask 0   Ask Ask 4   1   http://www.flipkey.com/cambria-vacation-rentals/p202618/    Ask     House   Ask 0   NULL    United States

And the Omni-query I that I am constructing to replace a few hundred lines of temp tables:

SELECT DISTINCT ROW_NUMBER() OVER(ORDER BY tbl_Properties.ID DESC) AS [RowNumber], tbl_Properties.ID, tbl_Properties.UserID, tbl_Properties.CountryID, tbl_Properties.tbl_detailsID, tbl_Properties.Name, 
tbl_Properties.[Description], tbl_Properties.Price, tbl_Properties.AddressLine1, tbl_Properties.AddressLine2, tbl_Properties.City, tbl_Properties.[State], tbl_Properties.Zip, tbl_Properties.AddressGPS,
 tbl_Properties.[Space],
 tbl_Properties.Amenities,
 tbl_Properties.Policies,
 tbl_Properties.URL,
 tbl_Properties.DateEntered,
 tbl_Properties.DateExpires,
 tbl_Properties.NumViews,
 tbl_Properties.IsCompanyProperty,
 tbl_Properties.EnforceMinStay,
 tbl_Properties.IsOtherSite,
 tbl_Properties.rate_Avg,
 tbl_Properties.isFeatured,
 tbl_Properties.DayPrice,
 tbl_Images.ImageURL,
 tbl_Details.Name,
 tbl_Details.check_in,
 tbl_Details.check_out,
 tbl_Details.currency,
 tbl_Details.bathroom_count,
 tbl_Details.pet,
 tbl_Details.unit_size,
 tbl_Details.elder,
 tbl_Details.handicap,
 tbl_Details.occupancy,
 tbl_Details.bedroom_count,
 tbl_Details.url As [LinkURL],
 tbl_Details.smoking,
 tbl_Details.unit_size_Units,
 tbl_Details.property_Type,
 tbl_Details.children,
tbl_Details.Minimum_stay,
tbl_Details.Minimum_stay_Unit,
 tbl_Countries.Name As [CountryName]
 FROM [tbl_Details] 
 INNER JOIN [tbl_Properties] ON [tbl_Details].[detailsID] = [tbl_Properties].[tbl_detailsID]
 INNER JOIN [tbl_Images] ON [tbl_Images].PropertyID = [tbl_Properties].ID
 INNER JOIN [tbl_Countries] ON [tbl_Countries].ID = [tbl_Properties].CountryID 

The query itself is, of course, not finished yet.

Answer 1

If your SQLServer version supports row_number() OVER (2008,2012 support)

select * from 
(select t.*, 
  row_number() over (partition by id order by id) as rownumber from t
) t1
where t1.rownumber=1

Here is the SQLFiddle example