在 Oracle PL/SQL 中编写一个简单的 SELECT 存储过程

Question

这是我的 SQL Server 存储过程，如下所示：

CREATE PROCEDURE passenger_details
AS
BEGIN
SELECT Full_Name, Age, Nationality, Category, Airline_Name, Class_Type
FROM Passenger, Ticket, Airline, Class
WHERE Passenger.Passenger_No=Ticket.Passenger_No AND Airline.Airline_No=Ticket.Airline_No AND Class.Class_No=Ticket.Class_No
END

EXECUTE passenger_details

SQL Server 中的上述存储过程成功运行。

然后我尝试在 Oracle PL/SQL 中执行相同的存储过程，如下所示：

CREATE OR REPLACE PROCEDURE passenger_details
(p_passenger_details OUT SYS_REFCURSOR) 
AS 
BEGIN 
OPEN p_passenger_details FOR
SELECT Full_Name, Age, Nationality, Category, Airline_Name, Class_Type
FROM Passenger, Ticket, Airline, Class
WHERE Passenger.Passenger_No=Ticket.Passenger_No AND Airline.Airline_No=Ticket.Airline_No AND Class.Class_No=Ticket.Class_No;
END passenger_details;

以上Oracle PL/SQL中的存储过程编译成功。

然后我尝试执行它，如下所示：

SET SERVEROUTPUT ON;
EXECUTE passenger_details;

在尝试执行存储过程时，我收到以下错误消息，如下所示：

Error starting at line : 12 in command -
BEGIN passenger_details; END;
Error report -
ORA-06550: line 1, column 7:
PLS-00306: wrong number or types of arguments in call to 'PASSENGER_DETAILS'
ORA-06550: line 1, column 7:
PL/SQL: Statement ignored
06550. 00000 -  "line %s, column %s:\n%s"
*Cause:    Usually a PL/SQL compilation error.
*Action:

Answer 1

您需要为过程传入 aREFCURSOR以用作其输出 ( OUT) 参数。

快速测试程序：

CREATE OR REPLACE PROCEDURE passenger_details
(p_passenger_details OUT SYS_REFCURSOR) 
AS 
BEGIN 
OPEN p_passenger_details FOR
SELECT 'test test' as Full_Name, 10 as Age, 'alien' as Nationality, 'foo' as Category, 
'Name' as Airline_Name, 'wobble' as Class_Type
FROM dual;
END passenger_details;
/

在 SQL*Plus 中测试：

SQL>变量 mycursor refcursor; 
SQL> execpassenger_details (:mycursor);

PL/SQL 过程成功完成。

SQL>打印 mycursor;

FULL_NAME 年龄 NATIO CAT Air CLASS_
--------- ---------- ----- --- ---- ------
test test 10 外星人 foo Name wobble

查询>

Answer 2

您可以使用dbms_sql返回隐式结果。这是 Oracle 12 中添加的一项功能，用于简化从 SQL Server 的迁移：

CREATE PROCEDURE passenger_details
AS
  c1 SYS_REFCURSOR;  
BEGIN

  open c1 for
  SELECT Full_Name, Age, Nationality, Category, Airline_Name, Class_Type
  FROM Passenger
    JOIN Ticket on Passenger.Passenger_No = Ticket.Passenger_No
    JOIN Airline ON Airline.Airline_No = Ticket.Airline_No
    JOIN Class ON Class.Class_No = Ticket.Class_No;

  DBMS_SQL.RETURN_RESULT(c1);
END;
/

请注意，我用显式JOIN运算符替换了古老且过时的隐式连接。