oracle的case语句转换成函数

[linkbin]

CASE
WHEN A.INAIM = 'O' AND A.SPECIALREASONCODE_T IS NULL THEN
A.BL
WHEN A.INAIM = 'O' AND A.SPECIALREASONCODE_T IS NOT NULL THEN
NVL(GET_EIRBILLNO(A.RECORDID), A.BL)
WHEN A.INAIM = 'I' THEN
GET_EIRBILLNO(A.RECORDID)
WHEN A.INAIM = 'D' THEN
NVL(GET_EIRBILLNO(A.RECORDID), GET_EIRBILLNO_S(A.RECORDID))
ELSE
A.BL
END

如上，我想把上面的语句做成一个函数，怎么改

CREATE OR REPLACE FUNCTION get_BOOKING_NBR()
...

[卖水果的net]

-- 要加四个参数，感觉还不如这样写，看着舒服；

create function fn(INAIM               varchar2,
                   SPECIALREASONCODE_T varchar2,
                   RECORDID            varchar2,
                   BL                  varchar2) 
return varchar2 
as
    ret varchar2(200);
begin
    select CASE
               WHEN INAIM = 'O' AND SPECIALREASONCODE_T IS NULL THEN
                BL
               WHEN INAIM = 'O' AND SPECIALREASONCODE_T IS NOT NULL THEN
                NVL(GET_EIRBILLNO(RECORDID), BL)
               WHEN INAIM = 'I' THEN
                GET_EIRBILLNO(RECORDID)
               WHEN INAIM = 'D' THEN
                NVL(GET_EIRBILLNO(RECORDID), GET_EIRBILLNO_S(RECORDID))
               ELSE
                BL
           END
      into ret
      from dual;
    return ret;
end;
/

[ghx287524027]

CREATE OR REPLACE FUNCTION get_BOOKING_NBR() return varchar2
is
变量定义
begin
	select 字段 into 变量 from 表
	if 判断相关变量 then
		return 。。
	elsif 判断变量 then
		return 。。
		………………
	end if;
end;

[linkbin]

引用 1 楼 wmxcn2000 的回复:

-- 要加四个参数，感觉还不如这样写，看着舒服；

create function fn(INAIM               varchar2,
                   SPECIALREASONCODE_T varchar2,
                   RECORDID            varchar2,
                   BL                  varchar2) 
return varchar2 
as
    ret varchar2(200);
begin
    select CASE
               WHEN INAIM = 'O' AND SPECIALREASONCODE_T IS NULL THEN
                BL
               WHEN INAIM = 'O' AND SPECIALREASONCODE_T IS NOT NULL THEN
                NVL(GET_EIRBILLNO(RECORDID), BL)
               WHEN INAIM = 'I' THEN
                GET_EIRBILLNO(RECORDID)
               WHEN INAIM = 'D' THEN
                NVL(GET_EIRBILLNO(RECORDID), GET_EIRBILLNO_S(RECORDID))
               ELSE
                BL
           END
      into ret
      from dual;
    return ret;
end;
/

都是高手