MySQL的存储过程:输出参数

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我有一个mysql存储过程( Google图书) ，一个例子是这样:

I have a mysql stored procedure from this (google book), and one example is this:

DELIMITER $$ DROP PROCEDURE IF EXISTS my_sqrt$$ CREATE PROCEDURE my_sqrt(input_number INT, OUT out_number FLOAT) BEGIN SET out_number=SQRT(input_number); END$$ DELIMITER ;

该程序编译正常. (我在ubuntu中使用MySQL查询浏览器).

The procedure compiles fine. (I am using MySQL Query Browser in ubuntu).

但是，当我调用该过程时:

However when I call the procedure:

CALL my_sqrt(4,@out_value);

(也在查询浏览器中)

它返回一个错误:

(1064) check the manual that correspond to the...

为什么这个例子不起作用?

Why isn't this example working?

推荐答案

无法复制.对我来说效果很好:

Unable to replicate. It worked fine for me:

mysql> CALL my_sqrt(4, @out_value); Query OK, 0 rows affected (0.00 sec) mysql> SELECT @out_value; +------------+ | @out_value | +------------+ | 2 | +------------+ 1 row in set (0.00 sec)

也许您应该粘贴整个错误消息，而不是对其进行总结.

Perhaps you should paste the entire error message instead of summarizing it.