mariaddb 函数中未声明的变量 compid

Question

我尝试创建通过电话号码（varchar）获取公司ID的函数

CREATE OR REPLACE FUNCTION getIdByPhone (cp CHAR(255))
RETURNS  INT
BEGIN 
SELECT id into compid 
FROM companies 
WHERE comp_phone1=cp;
RETURN compid;
END;

并且有错误：

Undeclared variable: compid

Answer 1

错误信息试图告诉你。您需要 declare 变量才能分配给它：

delimiter //

create function getidbyphone (cp char(255))
returns int
deterministic
begin 
    declare compid int;
    select id into compid from companies where comp_phone1 = cp;
    return compid;
end
//

delimiter;

这是一个Demo on DB Fiddle。