Question

phpMyAdmin: 3.5.7
MySQL: 5.5.29

我希望用户能够从数据库中的帖子编译几个不同的列表。应该使用以下函数将帖子添加到一个这样的列表中。它检查用户提供的列表ID是否与给定的用户ID匹配，然后检查列表是否已满，然后将帖子添加到列表中。

DELIMITER //

CREATE FUNCTION addToFav(inputKid INT, inputUid INT, listID INT, listLimit INT)
RETURNS VARCHAR(300)

BEGIN
DECLARE resultMsg VARCHAR(300);
DECLARE listExists INT; SET listExists = (SELECT COUNT(*) FROM fav_lists WHERE fav_list_id=listID AND uid=inputUid AND active=1);

IF 1 > listExists THEN SET resultMsg = 'LIST NON-EXISTANT';
ELSE 
    DECLARE listSize INT; 
        SET listSize = (SELECT COUNT(*) FROM fav_links WHERE fav_list_id=listID AND active=1);
    IF listSize = listLimit THEN SET resultMsg = 'LIST FULL';
        ELSE IF listSize > listLimit THEN SET resultMsg ='dbErr: LIST OVER LIMIT';
        ELSE 
            REPLACE INTO fav_links (kid, fav_list_id, active) VALUES (inputKid, listID, 1);
            SET resultMsg ='SUCCESS';
        END IF;
END IF;


RETURN resultMsg;
END //

DELIMITER ;

我将此代码输入phpMyAdmin的SQL控制台，它返回

#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 'DECLARE listSize INT; SET listSize = (SELECT COUNT(*) FROM fav_links W' at line 10

现在，如果我移动“有缺陷”的行，代码看起来像这样：

DELIMITER //

CREATE FUNCTION addToFav(inputKid INT, inputUid INT, listID INT, listLimit INT)
RETURNS VARCHAR(300)

BEGIN
DECLARE listSize INT; SET listSize = (SELECT COUNT(*) FROM fav_links WHERE fav_list_id=listID AND active=1);
DECLARE resultMsg VARCHAR(300);
DECLARE listExists INT; SET listExists = (SELECT COUNT(*) FROM fav_lists WHERE fav_list_id=listID AND uid=inputUid AND active=1);
[...]

此版本指向相同的错误，但在另一行：

#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 'DECLARE resultMsg VARCHAR(300); DECLARE listExists INT; SET listExists = (SELEC' at line 6

这让我相信问题可能是由于分隔符的错误使用造成的，但这就是我现在所拥有的。 PhpMyAdmin在SQL插入字段后面有一个分隔符字段，我尝试将其留空，填充;和//，但没有一个产生差异。

可能导致此问题的原因，以及如何解决？

Answer 1

您应该将变量声明保留在顶部。我也自由地重写了一些代码：

DELIMITER //

CREATE FUNCTION addToFav(inputKid INT, inputUid INT, listID INT, listLimit INT)
RETURNS VARCHAR(300)

BEGIN
DECLARE resultMsg VARCHAR(300);
DECLARE listSize INT; 

IF (NOT EXISTS (SELECT 1 FROM fav_lists WHERE fav_list_id=listID AND uid=inputUid AND active=1)) THEN 
    SET resultMsg = 'LIST NON-EXISTANT';
ELSE 
    SELECT COUNT(*) INTO listSize FROM fav_links WHERE fav_list_id=listID AND active=1;
    IF (listSize = listLimit) THEN 
        SET resultMsg = 'LIST FULL';
    ELSEIF (listSize > listLimit) THEN 
        SET resultMsg ='dbErr: LIST OVER LIMIT';
    ELSE 
        BEGIN
            REPLACE INTO fav_links (kid, fav_list_id, active) VALUES (inputKid, listID, 1);
            SET resultMsg ='SUCCESS';
        END;
    END IF;
END IF;

RETURN resultMsg;
END //

DELIMITER ;

如果您只想知道某些事物是否存在，请不要使用COUNT(*)。

Answer 2

使用ELSE IF MySQL ELSE Code there doesn't given space between IF`时，在and中尝试以下代码。还在顶部声明变量

DELIMITER //

CREATE FUNCTION addToFav(inputKid INT, inputUid INT, listID INT, listLimit INT) RETURNS VARCHAR(300)

BEGIN

    DECLARE resultMsg VARCHAR(300);
    DECLARE listExists INT; 
    DECLARE listSize INT; 

    SET listExists = (SELECT COUNT(*) FROM fav_lists WHERE fav_list_id=listID AND uid=inputUid AND active=1);

    IF (1 > listExists) THEN 
        SET resultMsg = 'LIST NON-EXISTANT';
    ELSE 
        SET listSize = (SELECT COUNT(*) FROM fav_links WHERE fav_list_id=listID AND active=1);
            IF listSize = listLimit THEN 
                SET resultMsg = 'LIST FULL';
            ELSEIF listSize > listLimit THEN 
                SET resultMsg ='dbErr: LIST OVER LIMIT';
            ELSE 
                REPLACE INTO fav_links (kid, fav_list_id, active) VALUES (inputKid, listID, 1);
                SET resultMsg ='SUCCESS';
            END IF;
    END IF;

RETURN resultMsg;
END //

DELIMITER ;

创建MySQL函数时出错（1064）

2 个答案: