游标嵌套的内层取不到值
我用pb11.5 mssql2000
代码：
DECLARE mycursor CURSOR FOR
SELECT DISTINCT jl.factory
FROM jl
WHERE (jl.jl_time >= :tt_date)AND
(jl.jl_time < :tom_date)
ORDER BY jl.factory asc;
open mycursor;
do while sqlca.sqlcode = 0
fetch mycursor into :factory;
if sqlca.sqlcode = 100 then
exit
end if
DECLARE mycursor2 CURSOR FOR
SELECT DISTINCT jl.norms
FROM jl
WHERE (jl.factory = :factory)AND
(jl.jl_time >= :tt_date)AND
(jl.jl_time < :tom_date)
ORDER BY jl.norms asc;
open mycursor2;
do while sqlca.sqlcode = 0
fetch mycursor2 into :norms;
if sqlca.sqlcode = 100 then
exit
end if
...................
loop
close mycursor2;
loop
close mycursor;

外层factory取到了值，可内层norms取不到。提示cursor is not open。
这段代码在pb8.0中动行的很好，可在pb11.5中就不行。高手看看是什么问题?
[解决办法]
为什么要用两个游标，这样一个游标不行吗

SELECT DISTINCT jl.factory, jl.norms
    FROM jl 
  WHERE (jl.jl_time >= :tt_date)AND 
        (jl.jl_time < :tom_date) 
ORDER BY jl.factory asc, jl.norms asc;