来自CursorOracle的确定性函数调用不起作用

我创建了一个简单的确定性函数，并使用游标中的选择查询调用它，如下所示

CREATE TABLE TEMP
(dt DATE); 

INSERT INTO   TEMP
SELECT SYSDATE FROM DUAL CONNECT BY LEVEL<=3;   
INSERT INTO   TEMP
SELECT SYSDATE+1 FROM DUAL CONNECT BY LEVEL<=3;     

COMMIT;

--2 distinct values
SELECT DISTINCT dt from TEMP;

包装功能

CREATE OR REPLACE PACKAGE dummy_fun
AUTHID CURRENT_USER
IS
    FUNCTION get_data(
                  p_date  IN DATE)
    RETURN DATE
    DETERMINISTIC;

END dummy_fun;
/


CREATE OR REPLACE PACKAGE BODY dummy_fun
IS
     FUNCTION get_data(
                  p_date IN DATE)
    RETURN DATE
    DETERMINISTIC
    IS
        
    BEGIN
         DBMS_OUTPUT.PUT_LINE('get_data with input (p_date=>'||p_date||' called)');
        
        RETURN p_date+1;

    END get_data;  
  
END dummy_fun;
/

函数调用 - 期望 get_data 在 2 个不同的日期只被调用两次，而如果我只调用这个 SQL，它只运行两次

DECLARE

CURSOR get_date
IS 
SELECT dummy_fun.get_data (
               dt)  from 
TEMP;

rec get_date%ROWTYPE;
v_date date;
BEGIN

OPEN get_date;
LOOP
  FETCH get_date INTO rec;
  EXIT WHEN get_date%NOTFOUND;
  NULL;
END LOOP;
CLOSE get_date;

END;
/

输出

get_data with input (p_date=>14-APR-21 called)
get_data with input (p_date=>14-APR-21 called)
get_data with input (p_date=>14-APR-21 called)
get_data with input (p_date=>14-APR-21 called)
get_data with input (p_date=>24-APR-21 called)
get_data with input (p_date=>24-APR-21 called)
get_data with input (p_date=>24-APR-21 called)
get_data with input (p_date=>24-APR-21 called)

**随着以下变化，它在光标中工作**

CHANGE 1 - IF THE FUNCTION IS CALLED IN THE WHERE CLAUSE 
CURSOR get_date
IS 
SELECT 1  from 
TEMP
WHERE trunc(sysdate+1)= trunc(ae9_common_code.dummy_fun.get_data (
               dt))

CHANGE 2 - Kind of Scalar subquery 
CURSOR get_date
IS 
SELECT * FROM (
SELECT ae9_common_code.dummy_fun.get_data (
               dt) from 
TEMP
WHERE 1=1)

CHANGE 3 - BULK COLLECT 

SELECT ae9_common_code.dummy_fun.get_data (
               dt) BULK COLLECT INTO v_dates from 
TEMP
WHERE 1=1;

##OUTPUT FOR ALL THE ABOVE CHANGES ARE##
get_data with input (p_date=>14-APR-21 called)
get_data with input (p_date=>24-APR-21 called)