Question

我不知道在查询中是否写错了，或者是否是逻辑错误。问题出现在倒数第二行。

<?php
include "connectdb.php";
$userId = mysql_real_escape_string($_GET["userId"]);

$q1 = mysql_query("SELECT * FROM visitors WHERE userId='userId'");
$num = mysql_num_rows($q1);
if($num==1){
    //user exists, update visits and unique values
    $visits = 0;
    while($row=mysql_fetch_array($q1)){
        $visits = $row["visits"] + 1;
        echo $row["visits"] + 1;
    }
    mysql_query("UPDATE visitors SET visits='$visits',unique='no' WHERE userId='$userId'");
    die();
}
//if there is no current visitor
mysql_query("INSERT INTO visitors(userId,visits,unique) VALUES('$userId','1','yes')");
?>

编辑：userId和访问都在数据库中设置为INT。

Answer 1

的 1

变化：

$q1 = mysql_query("SELECT * FROM visitors WHERE userId='userId'");

为：

$q1 = mysql_query("SELECT * FROM visitors WHERE userId=$userId");

的 2

删除SQL查询中$userId周围的单引号（因为它是INT）。它应该是这样的：

mysql_query("UPDATE visitors SET visits='$visits',`unique`='no' WHERE userId=$userId");

和

mysql_query("INSERT INTO visitors(userId,visits,`unique`) VALUES($userId,'1','yes')");

Answer 2

您应该为sql查询添加错误处理，但问题（在@DanielLisik指示的更正之后）是使用reserved word：unique。

将您的查询更改为：

mysql_query("INSERT INTO visitors(userId,visits,`unique`) VALUES('$userId','1','yes')");

您还应该考虑更改为PDO或mysqli，因为mysql_*函数已弃用。

Answer 3

i think first error in in variable name using  in $ql and second is $num==1 if in visitors table multiple record of thats user then this condition will be wrong ($num==1) so i think replace it with  this ($num>0) 

<?php
include "connectdb.php";
$userId = mysql_real_escape_string($_GET["userId"]);

$q1 = mysql_query("SELECT * FROM visitors WHERE userId='$userId' ");
$num = mysql_num_rows($q1);
if($num>0)
{
    //user exists, update visits and unique values
    $visits = 0;
    while($row=mysql_fetch_array($q1))
    {
        $visits = $row["visits"] + 1;
        echo $row["visits"] + 1;
    }
    mysql_query("UPDATE visitors SET visits='$visits',unique='no' WHERE userId='$userId'");
    die();
}
//if there is no current visitor
mysql_query("INSERT INTO visitors(`userId`,`visits`,`unique`) VALUES ('$userId','1','yes') ");
?>

插入查询不能与MySQL一起使用

3 个答案:

的 1

的 2