我需要一个函数

Question

我需要在 cm_customers$rt 表中创建一个函数，以向常驻客户验证 TAX_NUMBER 是否为 13 位，否则需要将列表显示到屏幕上，我创建了 juste select 但我需要一个函数，请帮助我

select  TAX_NUMBER,RESIDENT
from cm_customers$rt
WHERE length (TAX_NUMBER) =13 and resident = 'Y'
;

Answer 1

CREATE OR REPLACE FUNCTION f_tax
RETURN NUMBER
IS
    V_tax_number  int;

BEGIN
    SELECT tax_number 
    INTO V_tax_number
    FROM E_EMP
    WHERE LENGTH(tax_number ) < 13 
                 AND residence_type = 'Y';
    RETURN V_tax_number;

END;