oracle数据库的这个函数语句什么意思

if n_sxjjr = 0 then
select count(1) into n_jjrcount from gh_jjr where rq in (select to_char(arg_ghrq, 'MMDD') from dual) and rownum = 1;
if n_jjrcount = 1 then
n_sxjjr := 1;
end if;

n_sxjjr=0时，统计记录数量。
如果n_jjrcount 是1，默认n_sxjjr 为1.