Get unique row based on 2 columns with duplicate values - sql

Question

I have a table with 3 columns and 6 rows:
As you can see based on the highlighted red text, Ash and Joey have the same Last name and Street address i.e. column "Last" and column "Street" have a duplicate value. I would like to only get one of them.
Desired result would be to get rows without duplicate values on the "Last" and "Street" columns:
Where only one of Ash or Joey is retained (I just used Ash in this example, but Joey would be fine too - just need 1 or the other, not both).
Is this even possible? Any advise appreciated, thanks.
P.S. the “Street” column is actually on a different table so the picture of the graph represents 2 tables already joined.

Answer 1

Since you don't care which record of the duplicates survives you can give this a shot. It'll actually keep the first one alphabetically by First
DROP TABLE IF EXISTS #t;
CREATE TABLE #t (First VARCHAR(255), Last VARCHAR(255), Street VARCHAR(255));
INSERT #t SELECT 'Ash', 'Williams', '123 Main';
INSERT #t SELECT 'Ben', 'O''Shea', '456 Grand';
INSERT #t SELECT 'Claire', 'Port', '543 Jasper';
INSERT #t SELECT 'Denise', 'Stone', '543 Jasper';
INSERT #t SELECT 'Erica', 'Thomas', '789 Holt';
INSERT #t SELECT 'Joey', 'Williams', '123 Main';
WITH dupes AS (
SELECT First,
Last,
Street,
ROW_NUMBER() OVER (PARTITION BY Last, Street ORDER BY First) RowNum
FROM #t
)
SELECT First, Last, Street
FROM dupes
WHERE RowNum = 1;

Answer 2

On the assumption you want to retain the person with the first name alpabetically, you can use the ROW_NUMBER window function to generate a new row number for each duplicate and use that to filter out the dupes:
CREATE TABLE Peeps
(
FirstName NVARCHAR(20),
LastName NVARCHAR(20),
Street NVARCHAR(20)
)
INSERT INTO Peeps
VALUES
('Ash','Williams','123 Main'),
('Ben','O''Shea','456 grand'),
('Claire','Port','543 Jasper'),
('Denise','Stone','543 Jasper'),
('Erica','Thomas','789 Holt'),
('Joey','Williams','123 Main')
SELECT FirstName,
LastName,
Street
FROM (
SELECT FirstName,
LastName,
Street,
ROW_NUMBER () OVER (PARTITION BY LastName,Street ORDER BY FirstName) AS RowN
FROM Peeps
) a
WHERE RowN = 1
DROP TABLE Peeps