Oracle PL/SQL 似乎忽略了我函数的 WHERE 子句

Question

我有一个 table 的俱乐部成员，他们有一列状态，我想在下面的函数中用作过滤器。但是无论我将什么数字作为函数参数传递，结果总是相同的。计数始终与整个 table.

的总寄存器一起出现

CREATE OR REPLACE FUNCTION fn_count_members
(id_status in club.members.id_status%TYPE)
RETURN NUMBER IS
total club.members.id%TYPE:=0;
BEGIN
    SELECT COUNT(id) INTO total 
    FROM club.members m
    WHERE m.id_status = id_status; 
    RETURN total; 
END;

以及查询：

select id_status, fn_count_members(1) as total from club.members;

我在这里错过了什么？谢谢。

Answer 1

这是错误的：

(id_status in club.members.id_status%TYPE)
 ---------
 this

因为，在 where 子句中使用时

WHERE m.id_status = id_status

原来是where 1 = 1和returns一切，根本没有过滤。

将参数重命名为例如

(par_id_status in club.members.id_status%TYPE)

并将其用作

WHERE m.id_status = par_id_status

Answer 2

您有两个问题：

CREATE OR REPLACE FUNCTION fn_count_members(
  p_id_status in club.members.id_status%TYPE  -- change the parameter name to
                                              -- something different from the
                                              -- column name.
)
RETURN NUMBER IS
total club.members.id%TYPE:=0;
BEGIN
    SELECT COUNT(id) INTO total 
    FROM club.members m
    WHERE m.id_status = p_id_status;          -- and here
    RETURN total; 
END;
/

那你需要传入参数而不是使用1:

select id_status,
       fn_count_members(id_status) as total
from   club.members;

db<>fiddle here

Oracle PL/SQL 似乎忽略了我函数的 WHERE 子句

Oracle PL/SQL seems to ignore WHERE clause of my Function

oracle

plsql

oracle18c