MySql存儲過程錯誤[ERROR 1338（42000）：處理程序聲明后的游標聲明]

Question

我正在閱讀有關存儲過程的文章，這是代碼：

delimiter //

create procedure largest_order(out largest_id int) 
begin
  declare this_id int;
  declare this_amount float;
  declare l_amount float default 0.0;
  declare l_id int;

  declare done int default 0;
  declare continue handler for sqlstate '02000' set done = 1;
  declare c1 cursor for select orderid, amount from orders;

  open c1;
  repeat
    fetch c1 into this_id, this_amount;
    if not done then
      if this_amount > l_amount then
        set l_amount=this_amount;
        set l_id=this_id;
      end if;
    end if;
   until done end repeat; 
  close c1;

  set largest_id=l_id;

end
//

delimiter ;

我正在使用一個名為“mydatabase”的簡單數據庫。 運行上面的代碼后，它給了我這個錯誤： ERROR 1338 (42000): Cursor declaration after handler declaration什么問題，我該如何解決？

這是我第一次使用存儲過程。

Answer 1

每個MySql 文檔 ：

游標聲明必須出現在處理程序聲明之前以及變量和條件聲明之后。

所以我更新了代碼如下：

delimiter //

create procedure largest_order(out largest_id int) 
begin
  declare this_id int;
  declare this_amount float;
  declare l_amount float default 0.0;
  declare l_id int;

  -- 1. cursor finished/done variable comes first
  declare done int default 0;
  -- 2. the curser declaration and select
  declare c1 cursor for select orderid, amount from orders;
  -- 3. the continue handler is defined last
  declare continue handler for sqlstate '02000' set done = 1;


  open c1;
  repeat
    fetch c1 into this_id, this_amount;
    if not done then
      if this_amount > l_amount then
        set l_amount=this_amount;
        set l_id=this_id;
      end if;
    end if;
   until done end repeat; 
  close c1;

  set largest_id=l_id;

end
//

delimiter ;

現在工作正常。