MySql存储过程out id返回null

Question

我有一个存储过程，它插入到地址表中，它有 3 个输入参数和 1 个输出参数。如果我调用这个过程，参数为空

CREATE DEFINER=`root`@`localhost` 
PROCEDURE `insert_adress`(
                        in d varchar(50),
                        in r varchar(50),
                        in c varchar(50),
                        in adress_text varchar(255),
                        out id int)
BEGIN
    declare disc_id int;
    declare reg_id int;
    declare coun_id int;


if ((select count(*) from district where district.dist like d) <> 0)
    then set disc_id := (select id from district where district.dist like d);
    else
        insert into district(dist) values(d);
        set disc_id := (select max(id) from district);
end if;

if ((select count(*) from region where region.reg like r) <> 0)
    then set reg_id := (select id from region where region.reg like r);
    else
        insert into region(reg) values(r);
        set reg_id := (select max(id) from region);
end if;

if ((select count(*) from country where country.coun like c) <> 0)
    then set coun_id := (select id from country where country.coun like c);
    else
        insert into country(coun) values(c);
        set coun_id := (select max(id) from country);
end if;

insert into adress(district,region,country,adress_text) values(disc_id,reg_id,coun_id,adress_text);
set id := (select max(id) from adress);   
END

我称之为:

set @id = 0;
call mustaqil.insert_adress('test1', 'test1', 'test1', 'test1', @id);
select @id;

地区、地区、国家/地区表有“test1”行 我除了，out id，disc_id，reg_id，coun_id 应该是数字，但它是空的 P.S:存储过程插入行

Answer 1

只需更改 set id := (从地址中选择 max(id)); 到 从地址中选择 max(id) 到 id 中； 它应该有效