oracle - 甲骨文-PLS-00382 : expression is of wrong type in subtracting dates

Question

我在Oracle中编译以下函数时遇到麻烦

CREATE OR REPLACE FUNCTION fn1
return binary_double
as
Fecha  DATE;
Dias binary_double;
begin
dbms_output.put_line(CAST(TRUNC(CURRENT_DATE,'DD') AS DATE) - cast(current_timestamp as date));
return Dias;
end;

结果错误

Error(8,27): PLS-00382: expression is of wrong type

但是在函数体内运行相同的表达式

select CAST(TRUNC(CURRENT_DATE,'DD') AS DATE) - cast(current_timestamp as date) from dual

给出预期的结果-两个日期之间的天数

-0.0607060185185185185185185185185185185185

关于此功能可能有什么问题有任何想法吗？

Answer 1

采用:

begin
  dbms_output.put_line(TRUNC(CURRENT_DATE,'DD')  - cast( current_timestamp as date));
end;
/

Current_date返回数据类型DATE的值
Trunct也返回DATE。
因此，您正在尝试将DATE类型转换为DATE类型。