我有一些运行完美的 SQL 代码。当我尝试将它包装在一个过程中时，它无法创建，并且出现以下错误。有人可以解释一下问题是什么以及如何解决吗？

下面是我的测试用例。提前感谢所有回答的人。

Errors: PROCEDURE CREATE_accESS_HISTORY
Line/Col: 4/1 PLS-00428: an INTO clause is expected in this SELECT statement

ALTER SESSION SET NLS_DATE_FORMAT = 'MMDDYYYY HH24:MI:SS';

CREATE OR REPLACE TYPE nt_date IS TABLE OF DATE;

CREATE OR REPLACE FUNCTION generate_dates_pipelined(
          p_from IN DATE,p_to   IN DATE
        )
RETURN nt_date PIpelINED DETERMINISTIC
IS
  v_start DATE := TRUNC(LEAST(p_from,p_to));
  v_end   DATE := TRUNC(GREATEST(p_from,p_to));
BEGIN
     LOOP
         PIPE ROW (v_start);
         EXIT WHEN v_start >= v_end;
         v_start := v_start + INTERVAL '1' DAY;
     END LOOP;
     RETURN;
END generate_dates_pipelined;

Create table employees(employee_id NUMber(6),first_name  VARCHAR2(20),last_name   VARCHAR2(20),card_num    VARCHAR2(10),work_days   VARCHAR2(7)
                      );

ALTER TABLE employees ADD (CONSTRAINT employees_pk PRIMARY KEY (employee_id));

INSERT INTO employees (EMPLOYEE_ID,first_name,last_name,card_num,work_days)
WITH names AS (SELECT 1,'Jane','Doe','F123456','NYYYYYN'  
                 FROM dual UNION ALL 
               SELECT 2,'Madison','Smith','R33432','NYYYYYN'
                 FROM dual UNION ALL 
               SELECT 3,'Justin','Case','C765341','NYYYYYN'
                 FROM dual UNION ALL 
               SELECT 4,'Mike','Jones','D564311','NYYYYYN'
                 FROM dual  )
SELECT * FROM names;  
  
CREATE TABLE locations AS
SELECT level AS location_id,'Door ' || level AS location_name,CASE round(dbms_random.value(1,3)) 
                    WHEN 1 THEN 'A' 
                    WHEN 2 THEN 'T' 
                    WHEN 3 THEN 'T' 
       END AS location_type
  FROM dual
CONNECT BY level <= 50;

ALTER TABLE locations ADD (CONSTRAINT locations_pk PRIMARY KEY (location_id));

create table access_history(seq_num integer GENERATED BY DEFAULT AS IDENTITY (START WITH 1) NOT NULL,employee_id NUMber(6),card_num varchar2(10),location_id number(4),access_date date,processed NUMber(1) default 0
                           );

create or replace procedure create_access_history(p_start_date date,p_end_date date)
IS
BEGIN
     WITH cntr AS(SELECT LEVEL - 1 AS n
                    FROM dual
                 CONNECT BY LEVEL <= 25 -- Max number of rows per employee per date
                 ),got_location_num  AS(SELECT location_id,ROW_NUMber() OVER (ORDER BY location_id) AS location_num,COUNT(*) OVER () AS max_location_num
                                         FROM locations),employee_days AS(SELECT e.employee_id,e.card_num,d.column_value AS access_date,dbms_random.value (0,25) AS rn    -- 0 to max number of rows per employee per date
                                     FROM employees e
                                    CROSS JOIN TABLE (generate_dates_pipelined (p_start_date,p_end_date)) d),employee_n_days AS (SELECT ed.employee_id,ed.card_num,ed.access_date,1) AS lrn
                                        FROM employee_days ed
                                        JOIN cntr c ON c.n <= ed.rn
                                     )
     SELECT n.employee_id,n.card_num,l.location_id,n.access_date + NUMTODSINTERVAL(FLOOR(DBMS_RANDOM.VALUE(0,86399)),'SECOND') AS accESS_DATE 
       FROM employee_n_days n
       JOIN got_location_num l ON l.location_num = CEIL (n.lrn * l.max_location_num); 
       END;

EXEC  create_access_history (DATE '2021-08-01',DATE '2021-08-10');