Question

I have the following SQL Server 2008 table:

ID    Destination     Last Result
01    [phone]  Disconnect
02    [phone]  Duplicate
03    [phone]  Duplicate
04    [phone]  Duplicate
05    [phone]  Duplicate
06    [phone]  Busy
07    [phone]  Duplicate
08    [phone]  No Answer
09    [phone]  Duplicate

My goal is to dynamically set the ‘Last Result’ column for all matching phone numbers. So, in the example table above for Destination([phone]), the result for all matching phone numbers(555) 319-5170) with the value ‘Disconnect’. The sample update statement is below:

    UPDATE C
    SET [Last Result] = (
    SELECT Destination
                FROM Call
                WHERE [Last Result] NOT IN ('Duplicate','No Phone #')
                GROUP BY Destination
                HAVING COUNT(Destination) > 1)
    FROM Call C
    INNER JOIN
            (
                SELECT Destination
                FROM Call
                WHERE [Last Result] NOT IN ('Duplicate','No Phone #')
                GROUP BY Destination
                HAVING COUNT(Destination) > 1
            ) Dup ON Dup.Destination = C.Destination
    WHERE C.[Last Result] NOT IN ('Duplicate','No Phone #')

But I am getting an error:

Msg 512, Level 16, State 1, Line 1
Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression.

**EXPECTED OUTPUT**:

ID    Destination     Last Result
01    [phone]  Disconnect
02    [phone]  Disconnect
03    [phone]  Disconnect
04    [phone]  Duplicate
05    [phone]  Duplicate
06    [phone]  Busy
07    [phone]  Busy
08    [phone]  No Answer
09    [phone]  No Answer

Thanks in advance for any assistance with a possible solution.

Answer 1

You can look up the first Last Result with the row_number() window function. However, there has to be a way to define “first”. In the example, I’m assuming you have an identity column:

update  t1
set     [Last Result] = t2.[Last Result]
from    Table1 t1
join    (
        select  row_number() over (partition by Destination
                                   order by Id) as rn
        ,        *
        from     Table1
        ) t2
on      t1.Destination = t2.Destination
        and t2.rn = 1;

Example at SQL Fiddle.

If you do not have an identity column, please update the question with how you define “first”. There could be a CreateDt column for example.