select JAHR, KW, GROUP_CONCAT(distinct LOADNAME) as IN_LADEBESTAENDEN,

       (select GROUP_CONCAT(LOADSIZE) as LOADSIZES

          from CCVDCRLOADSIZES ls  

         where ls.JAHR=dcr.JAHR and ls.KW=dcr.KW 

         group by ls.JAHR, ls.KW) as LADEBESTANDGROESSEN 

  from CCDCRES dcr 

 group by JAHR, KW 

 order by JAHR, KW asc