Question

If I have rows with this data:

ID |Name        |ContractType|
---|------------|------------|
 1 |Aaron Shatz | 6-month    |
 2 |Jim Smith   |12-month    |
 3 |Jim Smith   | 6-month    |
 4 |Mark Johnson|12-month    |

I can’t use Id to determine which record to use: I have to use ContractType. I want to select all records from a table, but if there are records with the same Name value, I want to pick the 12-month contract record.

The result of the query should be:

ID |Name        |ContractType|
---|------------|------------|
 1 |Aaron Shatz | 6-month    |
 2 |Jim Smith   |12-month    |
 4 |Mark Johnson|12-month    |

Answer 1

This works only because the OP has confirmed that only two contract types are possible, and the one he wants (for each contractor) happens to be the one that orders first alphabetically. So a couple of coincidences make this solution straight-forward.

;WITH x AS
(
  SELECT ID, Name, ContractType, rn = ROW_NUMBER() OVER
    (PARTITION BY Name ORDER BY ContractType)
  FROM dbo.some_table
)
SELECT ID, Name, ContractType 
  FROM x
  WHERE rn = 1
  ORDER BY ID;

If you need to make this more dynamic, I suppose you could say:

DECLARE @PreferredContractType VARCHAR(32);
SET @PreferredContractType = '12-month';

;WITH x AS
(
  SELECT ID, Name, ContractType, rn = ROW_NUMBER() OVER
    (PARTITION BY Name ORDER BY CASE ContractType
      WHEN @PreferredContractType THEN 1 ELSE 2 END
    )
  FROM dbo.some_table
)
SELECT ID, Name, ContractType 
  FROM x
  WHERE rn = 1
  ORDER BY ID;