MySQL 在函数内调用存储过程

Question

所以我一直在到处寻找，试图了解如何在存储过程中调用函数，我在这里找到了这个例子：http://forums.mysql.com/read.php?98,175470,175476#msg-175476.

这帮助我构建了调用存储过程的函数，但是我一直收到此错误：

16:17:51    select regionUtilization(1,2) LIMIT 0, 1000 Error Code: 1415. Not allowed to return a result set from a function    0.000 sec

我要做的是调用以下存储过程并访问 OUT 变量。然后将其与输入的比较整数进行比较。

drop procedure if exists select_employeesByRegion_proc;
delimiter //
create procedure select_employeesByRegion_proc
(in search int, out result int)
    begin
        select t1.emp_id from (
        select employees.emp_id from branch
        inner join department
        on department.br_id = branch.br_id
        inner join employees
        on employees.dep_id = department.dep_id
        where branch.reg_id = search) as t1;
     set result:=FOUND_ROWS();
     end //
delimiter ;

以下是我目前拥有的功能

drop function if exists regionUtilization;
delimiter //
create function regionUtilization(search int, compare int)
    returns boolean
begin
    DECLARE temp int;
    call select_employeesByRegion_proc(search, temp);
    if temp >= compare then 
        return true;
    else
        return false;
    end if;
end //
delimiter ;

我还考虑过将存储过程的两个方面分离成单独的过程，方法是一个计数和另一个 return 结果，但是这仍然首先需要过程 select 一些数据会导致与我已经收到的错误相同的错误。

关于如何解决结果集错误的任何建议？我没有 returning 结果集，我只是使用该结果集来选择在我的函数中 return 是真还是假。提前致谢！

Answer 1

谢谢@Barmar 的回答。是的，我需要在我的过程中使用游标来适当地声明我的函数。

drop procedure if exists build_regionUtil_proc;
delimiter //
create procedure build_regionUtil_proc(in search int, inout result int)
    begin
        declare v_finished integer default 0;
        declare v_list int default 0;
        declare region_cursor cursor for
            select t1.emp_id from (
            select employees.emp_id from branch
            inner join department
            on department.br_id = branch.br_id
            inner join employees
            on employees.dep_id = department.dep_id
            where branch.reg_id = search) as t1;
        declare continue handler
            for not found set v_finished = 1;
        open region_cursor;
        get_results: loop
            fetch region_cursor into v_list;
            if v_finished = 1 then leave get_results;
            end if;
            set result = result + 1;
        end loop get_results;
        close region_cursor;
    end //
delimiter ;

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