oracle 有关for的疑问

[superfishmanweb]

(1)for 1..10与for 1...10有什么区别?
(2)1..10是升序,那降序又如何写?
(3)步长应该如何设定

[sasacat]

没有降序，只能1..10，不能1...10或10..1

关于步长可以这样处理，没有设置的地方的
FOR loop_index IN 1 .. 100
LOOP
IF MOD (loop_index, 2) = 0
THEN
/* We have an even number, so perform calculation */
calc_values (loop_index);
END IF;
END LOOP;

[superfishmanweb]

但为什么在plsql中能使用1...10(虽然结果是跳过,但没有出错).

[bobfang]

--递减循环
for i in reverse 1..100
loop
null;
end loop;

[superfishmanweb]

哦~~~,学习了.那在plsql中的1...10中的3点是怎么回事呢?

[waterfirer]

个人认为是误导 ：）

[CodeMagic]

Question 1:
没见过1...10这种写法。


Question 3:

Some languages provide a STEP clause, which lets you specify a different increment
(5 instead of 1 for example). PL/SQL has no such structure, but you can easily build
one. Inside the FOR loop, simply multiply each reference to the loop counter by the
new increment. In the following example, you assign today’s date to elements 5, 10,
and 15 of an index-by table:

DECLARE
TYPE DateList IS TABLE OF DATE INDEX BY BINARY_INTEGER;
dates DateList;
k CONSTANT INTEGER := 5; -- set new increment
BEGIN
FOR j IN 1..3 LOOP
dates(j*k) := SYSDATE; -- multiply loop counter by increment
END LOOP;
...
END;

[superfishmanweb]

THX