php删除sql查询不起作用

Question

<?php
    include('session.php');
?>

<?php
    $conn = new mysqli("127.0.0.1","root","","foo");
    if ($conn->connect_errno) {
        echo "Failed to connect to MySQL: (" . $conn->connect_errno . ") " .         $conn->connect_error;
    }
    $sew = $_SESSION['login_user'];
    $a = $_GET["en"];
    $l = 1;
    $d = -1;

    if($a == 1)
    {
        $sqlw = " INSERT into dlkeuser VALUES('$a','$sew')" ;

        if ($conn->query($sqlw) === FALSE) 
        {
            echo "you have already disliked the song";
        }
        else
        {
        //query1
            $sql = " DELETE FROM lkeuser WHERE userid = '$sew' AND songid = '$a' ";

        //query2
            $sql = "UPDATE liking
            SET count = count - 1 ";

            if ($conn->query($sql) === TRUE) {
                echo "you disliked the song";
            } 
            else {
                echo "Error: " . $sql . "<br>" . $conn->error;
            }
        }

在此 PHP 代码片段中，查询 1 不起作用，而查询 2 则正常。

我正在尝试根据用户 i/p($_GET["en"]) 在 dlkeuser(dislike) 表中插入 (songid, userid) 并删除从 lkeuser(like) 表记录(songid,userid)(如果存在)。 (songid,userid) 对是这里的复合主键。 count 是对歌曲的净喜欢/不喜欢。

Answer 1

让我们试试这个，

它会起作用

<?php
    include('session.php');
?>

<?php
    $conn = new mysqli("127.0.0.1","root","","foo");
    if ($conn->connect_errno) {
       echo "Failed to connect to MySQL: (" . $conn->connect_errno . ") " .           $conn->connect_error;
    }
    $sew = $_SESSION['login_user'];
    $a = $_GET["en"];
    $l = 1;
    $d = -1;

    if($a == 1)
    {
    $sqlw = " INSERT into dlkeuser VALUES('$a','$sew')";

        if ($conn->query($sqlw) === FALSE) 
        {
            echo "you have already disliked the song";
        }
        else
        {
        //query1
            $sql  = " DELETE FROM lkeuser WHERE userid = '$sew' AND songid = '$a' " ;

        //query2
            $sql1 = "UPDATE liking
            SET count = count - 1 ";

            if ($conn->query($sql) === TRUE) {
                echo "deleted the song";
            }

            if ($conn->query($sql1) === TRUE) {
                echo "you disliked the song";
            } 
            else {
                echo "Error: " . $sql . "<br>" . $conn->error;
            }
        }