oracle将多条数据合并成一条

select  t.col1,t.col2  ,wmsys.wm_concat(t.col3||' ') AS col3 , 
wmsys.wm_concat(t.col4||'') as col4,wmsys.wm_concat(t.col5||'') as col5,wmsys.wm_concat(t.col6||'') as col6 
from tablename t GROUP BY  t.col1,t.col2 ;