在设计饼图时为什么一定要有填充数据?
select yy,mm,sum(ogb14) ogb14
from (
select year(oga02) yy,month(oga02) mm,round(sum(ogb14)/10000000,2) ogb14
from oga_file,ogb_file
where oga01=ogb01
and oga09 = '2'
and ogapost='Y' and year(oga02)='${yy}'
group by year(oga02),month(oga02)
union
select null,1,0
from dual
)
group by yy,mm
我不加
union
select null,1,0
from dual
设计此报表就会显得很慢,基于打不开来,怎么解决?