Question

我在下面的代码中收到错误。错误是＃1329 - 无数据 - 提取，选择或处理零行。这究竟是什么意思，我做错了什么？感谢

create procedure cursorproc(OUT p_out DECIMAL(10,2)) begin

   declare l_salary, l_total DECIMAL(10,2);

   declare cur_1 cursor for select line_distance from elements;
       open cur_1;

   set l_total = 0;

   loop

      fetch cur_1 into l_salary;

         set l_total = l_total + l_salary;
         end loop;

   close cur_1;

   set p_out = l_total;

end;

Answer 1

当找不到更多数据时，您应该为光标DECLARE HANDLER：在docs中，您可以找到有关如何执行此操作的信息。

使用

DECLARE handler_type HANDLER FOR condition_value[,...] sp_statement

处理程序类型是以下之一：CONTINUE, EXIT or UNDO

所以你的代码会变成这样：

CREATE PROCEDURE cursorproc(OUT p_out DECIMAL(10,2)) 
BEGIN
   DECLARE l_salary, l_total DECIMAL(10,2);
   DECLARE _continue INT DEFAULT 0;

   DECLARE cur_1 CURSOR FOR SELECT line_distance FROM elements;   
   DECLARE CONTINUE HANDLER FOR NOT FOUND
    SET _continue =1;
   OPEN cur_1;
   SET l_total = 0;
   REPEAT
      FETCH cur_1 INTO l_salary;
      SET l_total = l_total + l_salary;
      UNTIL _continue = 1;
   END REPEAT;
   CLOSE cur_1;
   SET p_out = l_total;
END;

另请查看docs以获取更多信息。

Answer 2

这实际上与How to get rid of "Error 1329: No data - zero rows fetched, selected, or processed"相同，我提供了“found_rows（）”解决方案：http://tinky2jed.wordpress.com/technical-stuff/mysql/mysql-no-data-zero-rows-fetched-how-to-code-for-it/

我收到错误＃1329 - 没有数据 - 在MySQL中提取，选择或处理零行

2 个答案: