帮我改个错误，立即结帖

Question

这样行不：
select sum1 ,sum2 ,sum3 
from (select Company_Name,Tax_Type,sum(Tax_number) sum1 
    from table1 
    where substr(to_char(Tax_Time),1,6)=substr(to_char(sysdate,'YYYYMMDD'),1,6) 
        and Company_Name like '%北京%' 
    group by Company_Name,Tax_Type) tab_1,
    (select Company_Name,Tax_Type,sum(Tax_number) sum2 
    from table1 
    where substr(to_char(Tax_Time),1,4)=substr(to_char(sysdate,'YYYYMMDD'),1,4) 
        and Company_Name like '%北京%' 
    group by Company_Name,Tax_Type) tab_2,
    (select Company_Name,Tax_Type,sum(Tax_Number) sum3 
    from table1 
    where Company_Name like '%北京%' 
    group by Company_Name,Tax_Type) tab_3
where tab_1.Company_Name = tab_2.Company_Name(+)
    and tab_1.Tax_Type = tab_2.Tax_Type(+)
    and tab_1.Company_Name = tab_3.Company_Name(+)
    and tab_1.Tax_Type = tab_3.Tax_Type(+);

Answer 1

substr(to_char(ADD_MONTHS(sysdate,-12),'YYYYMMDD'),1,4)
select sum1 ,sum2 ,sum3 from (select Company_Name,Tax_Type,sum(Tax_number) sum1 from table1 where substr(to_char(Tax_Time),1,6)=substr(to_char(sysdate,'YYYYMMDD'),1,6) and Company_Name like '%北京%' group by Company_Name,Tax_Type) tab_1,(select Company_Name,Tax_Type,sum(Tax_number) sum2 from table1 where substr(to_char(Tax_Time),1,4)=substr(to_char(ADD_MONTHS(sysdate,-12),'YYYYMMDD'),1,4) and Company_Name like '%北京%' group by Company_Name,Tax_Type) tab_2,(select Company_Name,Tax_Type,sum(Tax_Number) sum3 from table1 where Company_Name like '%北京%' group by Company_Name,Tax_Type) tab_3;

Answer 2

substr(to_char(ADD_MONTHS(sysdate,-12),'YYYYMMDD'),1,4)这种语句可以直接换为to_char(ADD_MONTHS(sysdate,-12),'YYYY'),应该可以提高一下速度的