mysql中 储存过程 if exists 该怎么写呀?
CREATE PROCEDURE test(in ip int(20),in guid varchar(32))
BEGIN
  if exists ( SELECT * FROM a_usercheck WHERE guid = guid )
  BEGIN
  SELECT 'Hello Word!';
  END
END##


在 phpmyadmin 中执行sql命令,返回错误:
#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'BEGIN SELECT 'Hello Word!'; END END##' at line 4

正确该怎么写?

请高手指点一下.

谢谢.

------解决方案--------------------
delimiter $$
CREATE PROCEDURE test(in ip int(20),in guid varchar(32))
BEGIN
set @x = 0;
SELECT count(1) into @x FROM a_usercheck WHERE guid = guid;
if (@x > 0) then
SELECT 'Hello Word!';
end if;
END$$
------解决方案--------------------
注意红色部分。 另外你的 SELECT * FROM a_usercheck WHERE guid = guid 后面的WHERE永远为真。不要让变量与字段重名。
delimiter ##
CREATE PROCEDURE test(in ip int(20),in guid varchar(32))
BEGIN
 if exists ( SELECT * FROM a_usercheck WHERE guid = guid ) then
SELECT 'Hello Word!';
end if;
END##

SQL code

mysql> delimiter ##
mysql> CREATE PROCEDURE test(in ip int(20),in guid varchar(32))
    -> BEGIN
    ->  if exists ( SELECT * FROM a_usercheck WHERE guid = guid ) then
    ->      SELECT 'Hello Word!';
    ->   end if;
    -> END##
Query OK, 0 rows affected (0.08 sec)

mysql>