declare
v_Num number;
Begin
select Nvl(Num)
into v_Num
from Student
where SNo='000001';
End;
即查询SNo为000001的Num值;
现在情况是:如果SNo为000001的记录不存在,这时如何将v_Num值赋为0?
v_Num number;
Begin
select Nvl(Num)
into v_Num
from Student
where SNo='000001';
End;
即查询SNo为000001的Num值;
现在情况是:如果SNo为000001的记录不存在,这时如何将v_Num值赋为0?
declare
v_Num number;
Begin
select count(*) into v_num into v_Num from Student where SNo='000001';
if v_num=1 then
select nvl(Num,0) into v_Num from Student where SNo='000001';
else
v_num=0;
end;
End;好像解决的比较笨,后面高手接上
v_Num number;
Begin
select Num
into v_Num
from Student
where SNo='000001';
EXCEPTION
WHEN NO_DATA_FOUND THEN
v_Num := 0;
End;
select Decode(Count(*),1,Max(Num),NULL)
into v_Num
from Student
where SNo='000001';
要给分呀,我感觉这个最好的语句了呀。