Combineer meerdere rijen in één rij

U kunt zo geen dynamisch aantal kolommen hebben, maar u kunt uw gegevens samenvoegen in tekenreeks:

select
    s.ItemID, s.Code, s.Name,
    stuff(
        (
            select ', ' + CAST(sv.SearchValueID AS VARCHAR)
            from ItemSearch as sv
            where sv.ItemID = s.ItemID
            for xml path(''), type
        ).value('.', 'nvarchar(128)')
    , 1, 2, '') as SearchValues
from Item as s;

of u kunt rijen draaien met PIVOT command of handmatig (Ik geef de voorkeur aan de laatste benadering, het lijkt me gewoon flexibeler, maar pivot kan de hoeveelheid code in bepaalde situaties aanzienlijk verminderen ):

with cte as (
    select
        *,
        row_number() over(partition by sv.ItemID order by sv.SearchValueID) as row_num
    from ItemSearch as sv
)
select
    s.ItemID, s.Code, s.Name,
    max(case when sv.row_num = 1 then sv.SearchValueID end) as SearchValueID1,
    max(case when sv.row_num = 2 then sv.SearchValueID end) as SearchValueID2,
    max(case when sv.row_num = 3 then sv.SearchValueID end) as SearchValueID3,
    max(case when sv.row_num = 4 then sv.SearchValueID end) as SearchValueID4
from Item as s
    inner join cte as sv on sv.ItemID = s.ItemID
group by s.ItemID, s.Code, s.Name

U kunt de vorige instructie ook omzetten in dynamische SQL zoals dit:

declare @stmt nvarchar(max)

select
    @stmt = 
        isnull(@stmt + ',','') + 
        'max(case when sv.row_num = ' + cast(rn as nvarchar(max)) +
        ' then sv.SearchValueID end) as SearchValueID' + cast(rn as nvarchar(max))
from (
    select distinct row_number() over(partition by ItemID order by SearchValueID) as rn
    from ItemSearch
) as a

select @stmt = '
    with cte as (
        select
            *,
            row_number() over(partition by sv.ItemID order by sv.SearchValueID) as row_num
        from ItemSearch as sv
    )
    select
        s.ItemID, s.Code, s.Name,' + @stmt + '
    from Item as s
        inner join cte as sv on sv.ItemID = s.ItemID
    group by s.ItemID, s.Code, s.Name;'

exec dbo.sp_executesql @stmt = @stmt

sql fiddle-demo