Question

I am writing a query that will be used in a .NET application, therefore I would like the SQL Server 2008 o do much of the processing for me instead of the client PC that the application will run on.

I am trying to get data from a single table with an index value, based off of that index value I would like that item to placed in a specific column.

Here is an example:

table MAS:

MA      SN      Mindex
B275    7A1515  1
B276    7A1515  2
E530    7A1515  3
B291    7A1519  1
B292    7A1519  2
E535    7A1519  3
B301    7A2515  1
B302    7A2515  2
B331    7A2519  1
B332    7A2519  2

Here is the output I would like:

 SN      mi1     mi2     mi3
 7A1515  B275    B276    E530
 7A1519  B291    B292    E535
 7A2515  B301    B302    null
 7A2519  B331    B332    null

I tried doing the following query, it works with items with 3 indexes but if there are only two, it fills it with random data.

 select mas1.SN, mas1.MA as mi1,mas2.MA as mi2, mas3.MA as mi3
 from MAS ma1, MAS ma2, MAS ma3
 where mas1.SN = '7A1515' and mas1.Mindex = '1' and mas2.Mindex = '2' and mas3.Mindex = '3'

I was wondering if anyone would be able to point me in the right direction as I am still fairly new at writing these advanced queries.

Answer 1

As you are on SQL Server 2008 you can also use PIVOT but the old style way of doing it is often easier IMO.

SELECT 
    SN,
    MAX(CASE WHEN Mindex=1 THEN MA END) AS mi1,
    MAX(CASE WHEN Mindex=2 THEN MA END) AS mi2,
    MAX(CASE WHEN Mindex=3 THEN MA END) AS mi3
FROM MAS
GROUP BY SN