Database

select * from scheme.podetm d
left join scheme.stockm s on s.warehouse+s.product = d.warehouse+d.product
where d.qty_received >0 and d.inv_value_posted =0
and (s.analysis_a not in ( 'LNG', 'INFANTRUST') OR s.analysis_a IS NULL)

SELECT
    DataPoint,
    STUFF
    (
        (
            SELECT ',' + Site
            FROM YourTable As I
            WHERE I.DataPoint = O.DataPoint
            ORDER BY Site
            FOR XML PATH(''), TYPE
        ).value('.', 'varchar(max)')
        
        -- Remove the first comma:
        , 1, 1, ''
    ) As Sites
FROM
    YourTable As O
GROUP BY
    DataPoint
;

/*
Output:

DATAPOINT   SITES
-----------------
Power       CH
Temp        CH,KC
WindSpeed   CH,KC
*/