MySQL存储过程：输出参数？

Mysql> delimiter //
mysql> create procedure Sp_SQRT(IN Number1 INT, OUT Number2 FLOAT)
   -> Begin
   -> set Number2=sqrt(Number1);
   -> end;
   -> //
Query OK, 0 rows affected (0.24 sec)
mysql> delimiter ;

CALL yourStoredProcedureName(anyIntegerValue,@anyVariableName);

SELECT @anyVariableName;

mysql> call Sp_SQRT(36,@MySquareRootNumber);
Query OK, 0 rows affected (0.02 sec)

mysql> select @MySquareRootNumber;

+---------------------+
| @MySquareRootNumber |
+---------------------+
|                   6 |
+---------------------+
1 row in set (0.00 sec)