Предполагая, что 1 код производителя имеет только 1 идентификатор организации
SELECT
'1Qchubb'+ producercode, organisationid, 'demo@chubb.com',
producercode + N'ii', '123', @CurrentDate, 1, 0, 0
ROW_NUMBER() OVER(PARTITION BY PRODUCERCODE ORDER BY PRODUCERCODE, ORGANIZATIONID) AS RNK
INTO #TEMP
FROM
organisation
WHERE
producercode != N'00000'
AND producercode != ''
AND Active = 1
GROUP BY
producercode
INSERT INTO UserDetails (userlogin, Organisationid, emailaddress, username, userpassword, LastModifiedDate, SavedBy, ReceiveEmail, [Disabled])
OUTPUT inserted.UserID INTO _temp_new_user_details
SELECT * FROM #TEMP WHERE RNK = 1
При условии, что 1 код производителя имеет несколько идентификаторов организации, которые различаются в зависимости от уникального кода производителя и идентификатора организации
SELECT
'1Qchubb'+ producercode, organisationid, 'demo@chubb.com',
producercode + N'ii', '123', @CurrentDate, 1, 0, 0
ROW_NUMBER() OVER(PARTITION BY PRODUCERCODE, ORGANIZATIONID ORDER BY PRODUCERCODE, ORGANIZATIONID) AS RNK
INTO #TEMP
FROM
organisation
WHERE
producercode != N'00000'
AND producercode != ''
AND Active = 1
GROUP BY
producercode
INSERT INTO UserDetails (userlogin, Organisationid, emailaddress, username, userpassword, LastModifiedDate, SavedBy, ReceiveEmail, [Disabled])
OUTPUT inserted.UserID INTO _temp_new_user_details
SELECT * FROM #TEMP WHERE RNK = 1