PHP准备好的语句返回-1 [英] PHP Prepared Statement Returns -1

问题描述

我已经使用准备好的语句已有一段时间了，而且我从未遇到任何问题.

I've been using prepared statements for a little while now and I've never had any problems.

现在我正在尝试:

$sql="SELECT PhotoID,Caption FROM Photos WHERE EntityID=? AND TypeID=? LIMIT ?,?";

$iDB = new mysqliDB(); // Extends mysqli

$stmt = $iDB->prepare($sql);

$stmt->bind_param('iiii',$entityID,$typeID,$minRange,$maxRange);

$stmt->execute();

$stmt->bind_result($photoID,$caption);

echo("Affected={$stmt->affected_rows}");

这将打印-1.我已经进行了三次测试，设置bindParam中的所有4个值都已设置，并且将带有相应值的sql查询粘贴到myAdmin中后即可正常工作.

This prints -1. I have triple tested that all 4 values in bindParam are set, and that the sql query works when pasted into myAdmin with the respective values.

您知道是什么原因造成的吗?

Any idea what may be causing this?

:我在网上找到了答案，显然我需要使用$ stmt-> store_result();.执行后..但我不确定现在是否需要它.

: I found the answer online, apparently I need to use $stmt->store_result(); after executing.. but I am not sure it's needed now and never before..

推荐答案

每个mysqli函数/方法可能失败.根据扩展class mysqli的方式，您可能必须测试每个返回值.如果方法返回false，则会发生错误，并且错误消息将存储在mysqli或语句对象的属性中.

Each mysqli function/method can fail. Depending on how you have extended class mysqli you probably have to test each and every return value. If a method return false an error occurred and the error message is stored in a property of either the mysqli or the statement object.

$sql="SELECT PhotoID,Caption FROM Photos WHERE EntityID=? AND TypeID=? LIMIT ?,?";

$iDB = new mysqliDB(); // Extends mysqli
if ($iDB->connect_error) {
  printf('connect error (%d) %s', $iDB->connect_errno, htmlspecialchars($iDB->connect_error));
  die;
}

$stmt = $iDB->prepare($sql);
if ( false===$stmt ) {
  printf('prepare failed: %s', htmlspecialchars($iDB->error));
  die;
}

$rc = $stmt->bind_param('iiii',$entityID,$typeID,$minRange,$maxRange);
if ( false===$rc ) {
  printf('bind_param failed: %s', htmlspecialchars($stmt->error));
  die;
}

$rc = $stmt->execute();
if ( false===$rc ) {
  printf('execute failed: %s', htmlspecialchars($stmt->error));
  die;
}

$rc = $stmt->bind_result($photoID,$caption);
if ( false===$rc ) {
  printf('bind_result failed: %s', htmlspecialchars($stmt->error));
  die;
}

// echo("Affected={$stmt->affected_rows}");

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