oracle - PL/SQL 检查日期是否有效

Question

如果我在 PL/SQL 中有一个日期格式 DDMM 并且我想验证它。正确的做法是什么？

DD 是日，MM 是蛾。

For an example:
0208 - is a valid date
3209 - is not a valid date
0113 - is not a valid date.

Answer 1

例如，您可以编写一个像这样的函数:

create or replace function is_valid(p_val in varchar2)
return number
is
  not_a_valid_day   exception;
  not_a_valid_month exception;
  pragma exception_init(not_a_valid_day, -1847);
  pragma exception_init(not_a_valid_month, -1843);
  l_date date;
begin
  l_date := to_date(p_val, 'ddmm');
  return 1;
exception
  when not_a_valid_day or not_a_valid_month
  then return 0;
end;



SQL> with test_dates(dt) as(
  2    select '0208' from dual union all
  3    select '3209' from dual union all
  4    select '0113' from dual
  5  )
  6  select dt, is_valid(dt) as valid
  7    from test_dates
  8  /

DT        VALID
---- ----------
0208          1
3209          0
0113          0