MySQL创建过程，遇到一个奇怪的bug

mysql> CREATE PROCEDURE sp3(IN p_id SMALLINT UNSIGNED,OUT userNums SMALLINT UNSIGNED)

    -> BEGIN

    -> DELETE FROM test WHERE id=p_id;

    -> SELECT COUNT(id) FROM test INTO userNums;

    -> END

    -> //
Query OK, 0 rows affected (0.02 sec)

mysql> CREATE PROCEDURE sp3(IN p_id SMALLINT UNSIGNED,OUT userNums SMALLINT UNSIGNED)

    ->

    -> DELETE FROM test WHERE id_pid;

    -> SELECT COUNT(id) FROM test INTO userNums;

    -> END

    -> //

Query OK, 0 rows affected (0.00 sec)

ERROR 1327 (42000): Undeclared variable: userNums

第二个缺少BEGIN，声明的变量在过程体中不起作用，至于为什么，后面再研究。