Question

I have raw data that looks as follows:

I want to perform a T-SQL query to put the data in the following form:

It’s almost like an UnPivot type query, but I don’t know how to go about doing it. Also, one clarification. The value for the LastModifiedTime column can be any one of the five values for each SubGroupId. It wouldn’t matter exactly which one it was.

Thanks very much for your help.

Answer 1

There are two ways you can do this, either using a Static PIVOT where you hard code the values in that you need to PIVOT:

create table temp
(
    subgroupid int,
    coater varchar(10),
    metricTypeDescriptor varchar(5),
    subgroupvalue decimal(20, 6),
    valuedescription varchar(50),
    lastmodfiedtime datetime
)

insert into temp values(28099, 'VA_A', 'CdSim', 2.99886, 'Average', '2012-05-03 20:55:02.14')
insert into temp values(28099, 'VA_A', 'CdSim', 2.57201, 'Minimum', '2012-05-03 20:55:02.14')
insert into temp values(28099, 'VA_A', 'CdSim', 3.1646, 'Maximum', '2012-05-03 20:55:02.143')
insert into temp values(28099, 'VA_A', 'CdSim', 0.22082, 'Standard Deviation', '2012-05-03 20:55:02.153')
insert into temp values(28099, 'VA_A', 'CdSim', 0.59259, 'xWebRange', '2012-05-03 20:55:02.157')

insert into temp values(28102, 'VA_A', 'CdSim', 2.9091, 'Average', '2012-05-03 21:00:01.27')
insert into temp values(28102, 'VA_A', 'CdSim', 2.67619, 'Minimum', '2012-05-03 21:00:01.27')
insert into temp values(28102, 'VA_A', 'CdSim', 3.17471, 'Maximum', '2012-05-03 21:00:01.27')
insert into temp values(28102, 'VA_A', 'CdSim', 0.191868, 'Standard Deviation', '2012-05-03 21:00:01.27')
insert into temp values(28102, 'VA_A', 'CdSim', 0.49852, 'xWebRange', '2012-05-03 21:00:01.27')

insert into temp values(28104, 'VA_A', 'CdSim', 3.05835, 'Average', '2012-05-03 21:05:01.383')
insert into temp values(28104, 'VA_A', 'CdSim', 2.80336, 'Minimum', '2012-05-03 21:05:01.387')
insert into temp values(28104, 'VA_A', 'CdSim', 3.17943, 'Maximum', '2012-05-03 21:05:01.387')
insert into temp values(28104, 'VA_A', 'CdSim', 0.158743, 'Standard Deviation', '2012-05-03 21:05:01.39')
insert into temp values(28104, 'VA_A', 'CdSim', 0.37607, 'xWebRange', '2012-05-03 21:05:01.40')

select subgroupid, coater, metrictypedescriptor
    , [average]
    , [maximum]
    , [minimum]
    , [standard deviation]
    , lastmodfiedtime
from 
(
    select t1.subgroupid, t1.coater, t1.metrictypedescriptor, t1.valuedescription, t1.subgroupvalue, t2.lastmodfiedtime
    from temp t1
    left join 
    (
        select subgroupid, max(lastmodfiedtime) as lastmodfiedtime
        from temp 
        group by subgroupid
    ) t2
        on t1.subgroupid = t2.subgroupid
) x
pivot
(
    max(subgroupvalue)
    for valuedescription in([Average], [Minimum], [Maximum], [Standard Deviation])
) p


drop table temp

Or you can do this via a dynamic Pivot where you create the list of columns on the fly and then PIVOT them:

DECLARE @cols AS NVARCHAR(MAX),
    @query  AS NVARCHAR(MAX);

select @cols = STUFF((SELECT distinct ',' + QUOTENAME(c.valuedescription) 
            FROM temp c
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')

set @query = 'SELECT subgroupid, coater, metrictypedescriptor, ' + @cols + ', lastmodfiedtime from 
            (
                select t1.subgroupid, t1.coater, t1.metrictypedescriptor, t1.valuedescription, t1.subgroupvalue, t2.lastmodfiedtime
                from temp t1
                left join 
                (
                    select subgroupid, max(lastmodfiedtime) as lastmodfiedtime
                    from temp 
                    group by subgroupid
                ) t2
                    on t1.subgroupid = t2.subgroupid
                ) x
            pivot
            (
                max(subgroupvalue)
                for valuedescription in(' + @cols + ')
            ) p '

execute(@query)