如何定义将用作函数内的 IN 参数的参数？

Question

我想做一个接收两个参数的函数。 第一个代表一组员工的工资，第二个代表一组部门的代码。 P_IN_SALARIES 和 P_IN_DEPARTMENTS_CODES 参数都将用作查询的 IN 函数中的参数，如下面的代码所示：

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 语句中的 IN 参数的类型是什么？
• 是否有一个通用的我可以使用以便在偶尔的数据库交换（例如到 Oracle）中允许某种可移植性？
• 如何在休眠查询中调用此函数？

Answer 1

在 Oracle 中，您可以使用集合数据类型：

CREATE TABLE number_list IS TABLE OF NUMBER;

然后您可以使用MEMBER OF运算符而不是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;
/