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Editorial Team
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Asked: 2026-06-17T08:27:05+00:00

I have the following query that returns a comma separated list of email ids

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I have the following query that returns a comma separated list of email ids for the selected user.

CREATE TABLE TEST
(
    ID INT PRIMARY KEY,
    FIRSTNAME VARCHAR(30) NOT NULL,
    LASTNAME VARCHAR(30) NOT NULL,
    EMAIL VARCHAR(50)
)

INSERT INTO TEST VALUES (1, 'Tom', 'Lew', 'tom@hotmail.com')
INSERT INTO TEST VALUES (2, 'Tom', 'Lew', 'tom@hotmail.com')
INSERT INTO TEST VALUES (3, 'Jack', 'Stan', 'jstan@hotmail.com')
INSERT INTO TEST VALUES (4, 'Tom', 'Reed', 'tomreed@hotmail.com')
INSERT INTO TEST VALUES (5, 'Tom', 'Reed', 'tomr@hotmail.com')
INSERT INTO TEST VALUES (6, 'Tom', 'Reed', 'treed@hotmail.com')

DECLARE @result VARCHAR(MAX)

    SELECT @result = COALESCE(@result + ',', '') + [EMAIL]
    FROM [TEST]
    WHERE [FirstName] = 'Tom' AND [LastName] = 'Reed'

    SELECT @result

I need to modify the query so that it returns only one value either
– one email Id if there is only one email id associated with ‘Tom Reed’
– string ‘multiple’ if more than one email ids found for ‘Tom Reed’

I somehow was able to get the desired result but not sure about the performance. In real scenario this table will have thousands of records and will be joined to other tables.

SELECT
    DISTINCT
    CASE 
        WHEN CNT = 1 THEN EMAIL
        ELSE 'MULTIPLE'
    END
FROM (SELECT 
    ID, EMAIL,
    COUNT(*) OVER() CNT
    FROM TEST
    WHERE [FirstName] = 'Tom' AND [LastName] = 'Reed') T

Sorry, if the subject line and the content doesn’t match. Was not sure about the description.

Desired Results:

  1. If queried on ‘Tom Reed’

    Output: Multiple

  2. If queried on ‘Tom Lew’

    Output: Multiple

  3. If queried on ‘Jack Stan’

    Output: jstan@hotmail.com
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1 Answer

  1. Editorial Team

    I think this would work (untested):

    SELECT DISTINCT
    FirstName, 
    LastName,  
    CASE 
      WHEN COUNT(Email) OVER (PARTITION BY FirstName,LastName) = 1 
      THEN Email 
      ELSE 'Multiple' END
FROM Test

    And if you need just the word by the passed in params:

    SELECT DISTINCT
    CASE 
      WHEN COUNT(Email) OVER (PARTITION BY FirstName,LastName) = 1 
      THEN Email 
      ELSE 'Multiple' END
FROM Test
WHERE FirstName = 'Tom' 
   AND LastName = 'Reed'

    This should return either the Email or the word Multiple.

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