MYSQL存储过程选择语句选择不正确的ID

Question

当我谈到存储过程时，我不是最懂得知识的人，而这个问题正在让我大跌眼镜！

基本上我只是试图运行一个简单的更新语句，但我选择更新行的用户ID不正确，当我在过程中运行它时，但如果我在过程外运行相同的select语句它会返回预期结果。

DELIMITER $$ 
CREATE PROCEDURE catchUpBbs_Users() 
    BEGIN 
    DECLARE done INT DEFAULT 0; 
    DECLARE deleteUser, keepUser VARCHAR(255); 
    DECLARE id INT; 
    DECLARE cur1 CURSOR FOR SELECT u.username, b.username, b.id from users u RIGHT  JOIN bbs_users b ON u.username = b.username WHERE u.username IS NULL; 
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;  
    OPEN cur1; 
     allusers: LOOP 
      FETCH cur1 INTO keepUser, deleteUser, id; 
      IF done THEN 
       LEAVE allusers; 
      END IF; 
IF deleteUser != 'anonymous' THEN 

-- This is where the problems start 

-- Just for test purposes, returns correct id and username 
SELECT id, username FROM bbs_users WHERE username = deleteUser; 

-- Just for test purposes, return INCORRECT id, but the CORRECT username 
SELECT id, username FROM bbs_users WHERE username = 'anonymous'; 

-- The update statement that does not work as I want it to, sets the user_id to be what it already it, so no updates occur 
UPDATE bbs_posts SET user_id = (SELECT id FROM bbs_users WHERE username = 'anonymous') WHERE user_id = (SELECT id FROM bbs_users WHERE username = deleteUser); 

-- delete the user from the bbs_users table 
DELETE FROM bbs_users WHERE username = deleteUser; 

END IF; 
    END LOOP allusers; 
    CLOSE cur1; 
END; 

$$ 
DELIMITER ; 

当我调用该过程的两个测试选择语句返回：

1）这些结果都正确

SELECT id, username FROM bbs_users WHERE username = deleteUser; 
+------+----------+ 
| id | username | 
+------+----------+ 
| 13 | deleteme | 
+------+----------+ 

2）ID不正确，但用户名是不正确，该ID应为1

SELECT id, username FROM bbs_users WHERE username = 'anonymous'; 
+------+-----------+ 
| id | username | 
+------+-----------+ 
| 13 | anonymous | 
+------+-----------+ 

当我运行相同的，减去变量，选择语句之外该过程都返回正确的结果

1）这些结果都是正确的

SELECT id, username FROM bbs_users WHERE username = 'deleteme'; 
+----+----------+ 
| id | username | 
+----+----------+ 
| 13 | deleteme | 
+----+----------+ 

2）这些结果都是正确的

SELECT id, username FROM bbs_users WHERE username = 'anonymous'; 
+----+-----------+ 
| id | username | 
+----+-----------+ 
| 1 | anonymous | 
+----+-----------+ 

我在做什么错？在使用存储过程时，在选择和变量时是否会漏掉某些东西？

任何帮助或建议，将不胜感激

Answer 1

的问题是，你有你的光标定义了一个名为id标量和您选择进去，所以无论光标的内部SELECT语句的使用它存储所有对id的引用的标量值。

为了得到“正确”的价值，你需要删除所有不确定性：

-- Just for test purposes, returns correct id and username 
SELECT b.id, b.username FROM bbs_users b WHERE b.username = deleteUser; 

-- Just for test purposes, return INCORRECT id, but the CORRECT username 
SELECT b.id, b.username FROM bbs_users b WHERE b.username = 'anonymous'; 

Answer 2

你tryed重复了一句“Fetch CUR1 INTO keepUser，deleteUser，ID”结束后，当且在结束循环之前...

Answer 3

以下工作是否更好。清理了多次有效地执行相同查询的位置。对不起，如果我误解了这个问题 - 但是如果我理解正确，那么下面的查询应该更有效一些。也删除所有不明确的字段名称。

DELIMITER $$ 
CREATE PROCEDURE catchUpBbs_Users() 
    BEGIN 
    DECLARE done INT DEFAULT 0; 
    DECLARE oldID INT; 
    DECLARE newID INT; 
    DECLARE cur1 CURSOR FOR 
     SELECT b.id 
     FROM users u 
     RIGHT JOIN bbs_users b 
     ON u.username = b.username 
     WHERE u.username IS NULL; 

    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;  

    // Get the new id 
    SELECT id INTO newID FROM bbs_users WHERE username = 'anonymous'; 

    OPEN cur1; 
     allusers: LOOP 
      FETCH cur1 INTO oldID; // b.id 

      IF done THEN 
       LEAVE allusers; 
      END IF; 

      IF deleteUser != 'anonymous' THEN 

       -- Just for test purposes, returns correct id and username 
       SELECT id, username FROM bbs_users WHERE id = oldID; 

       -- Just for test purposes, return INCORRECT id, but the CORRECT username 
       SELECT id, username FROM bbs_users WHERE id = newID; 

       UPDATE bbs_posts SET user_id = newID WHERE user_id = oldID; 

       -- delete the user from the bbs_users table 
       DELETE FROM bbs_users WHERE id = oldID; 

      END IF; 
     END LOOP allusers; 
    CLOSE cur1; 
END; 

$$ 
DELIMITER ;