Mysql 插入带有值的查询并选择作为子查询

Question

我尝试了多种解决方案，但无法使我的查询正常工作。

我正在尝试创建一个点赞系统，该系统在代码中将检查被点赞的项目是否存在以及尚未被点赞。

我认为我已经接近查询，但我不断收到错误。

变量“$this_is_liked”预定义为值“Yes”，变量“$liked_user_id”预定义为登录用户的值(本例中为1)，然后“$liked_item_id”被拉取来自 pms_inventory 表，同时我试图让它检查项目 id 是否存在，并且尚未被喜欢。

下面是我的代码，然后是错误。

        if(isset($_POST['type'], $_POST['itemid'], $_POST['liked']))  {
            include_once('connectdb.php');
            include_once('global.php');
            $liked_item_id = (int)$_POST['itemid']; // Liked Item ID
            $liked_user_id = (int)$_SESSION['id']; // User ID
            $this_is_liked = $_POST['liked']; // Value of "Yes"
        mysql_query("
        INSERT INTO pms_inventory_likes 
            (
            liked,
            user_id, 
            item_id, 
            )
            VALUES
            (
            SELECT 
            {$this_is_liked}, {$liked_user_id}, {$liked_item_id} 
            FROM pms_inventory
            WHERE EXISTS (
                SELECT id 
                FROM pms_inventory
                WHERE id = {$liked_item_id})
            AND NOT EXISTS (
                SELECT id 
                FROM pms_inventory_likes 
                WHERE user_id = {$liked_user_id} 
                AND item_id = {$liked_item_id} 
                AND liked = 'Yes')  
            )
            LIMIT 1
        ") or die(mysql_error());
    }

这是错误:

    <span>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 ')
            VALUES
            (
            SELECT 
            Yes, 1, 40 
            FROM pms_inventory
            ' at line 6</span>

我不确定我是否正确嵌套了“SELECT”，或者是否正确标记了值。

如果需要更多信息，请告诉我!

Answer 1

试试这个，它可能会帮助你......

              INSERT INTO pms_inventory_likes 
                (liked,
                user_id, 
                item_id) 

               SELECT {$this_is_liked}, {$liked_user_id}, {$liked_item_id} FROM pms_inventory

                WHERE EXISTS (
                    SELECT id 
                    FROM pms_inventory
                    WHERE id = {$liked_item_id})

                AND NOT EXISTS (
                    SELECT id 
                    FROM pms_inventory_likes 
                    WHERE user_id = {$liked_user_id} 
                    AND item_id = {$liked_item_id} 
                    AND liked = "Yes")  
                LIMIT 1

有关更多引用信息，请参阅以下链接:

Oracle insert if not exists statement

http://www.techonthenet.com/oracle/insert.php

http://docs.oracle.com/cd/E17952_01/refman-5.1-en/exists-and-not-exists-subqueries.html