update a
set c1=cast((select count(*) from tbl1 where c2=a.c2 and c2=a.c3 and c4=a.c4 and c5<=a.c5) as varchar)
from tbl1 a
where c1=''
set c1=cast((select count(*) from tbl1 where c2=a.c2 and c2=a.c3 and c4=a.c4 and c5<=a.c5) as varchar)
from tbl1 a
where c1=''
set c1=cast((select count(*) from tbl1 where c5<=a.c5) as varchar)
from tbl1 a
where c1=''
这样可以了,谢谢Yang,结贴