如何定義將用作函數內的 IN 參數的參數？

Question

我想做一個接收兩個參數的函數。 第一個代表一組員工的工資，第二個代表一組部門的代碼。 P_IN_SALARIES 和 P_IN_DEPARTMENTS_CODES 參數都將用作查詢的 IN 函數中的參數，如下面的代碼所示：

CREATE OR REPLACE FUNCTION public.get_employees_id(P_IN_SALARIES WHICH_TYPE_COMES_HERE, P_IN_DEPARTMENTS_CODES WHICH_TYPE_COMES_HERE)
 RETURNS text
 LANGUAGE plpgsql
AS $function$
declare
    v_employees_ids text;
begin

    select STRING_AGG(employee.id || '', ',') into v_employees_ids
    from employee 
    inner join departament on department.id = employee.departament_id
    where employee.salary in (P_IN_SALARIES)
    and department.code in (P_IN_DEPARTMENTS_CODES);

    RETURN v_employees_ids;
END;
$function$

• SQL 語句中的 IN 參數的類型是什么？
• 是否有一個通用的我可以使用以便在偶爾的數據庫交換（例如到 Oracle）中允許某種可移植性？
• 如何在休眠查詢中調用此函數？

Answer 1

在 Oracle 中，您可以使用集合數據類型：

CREATE TABLE number_list IS TABLE OF NUMBER;

然后您可以使用MEMBER OF運算符而不是IN ：

CREATE FUNCTION public.get_employees_id(
  P_IN_SALARIES          IN number_list,
  P_IN_DEPARTMENTS_CODES IN number_list
) RETURNS VARCHAR2
IS
    v_employees_ids VARCHAR2(4000);
BEGIN
    SELECT LISTAGG( id, ',' ) WITHIN GROUP ( ORDER BY id )
    INTO   v_employees_ids
    FROM   employee e 
           inner join departament d
           on ( d.id = e.departament_id )
    WHERE  e.salary MEMBER OF P_IN_SALARIES
    AND    d.department.code MEMBER OF P_IN_DEPARTMENTS_CODES;

    RETURN v_employees_ids;
END;
/