我正在尝试获取特定项目上的评论数量。MySQL SELECT COUNT returns NULL
$stmt1 = $conn->prepare("SELECT COUNT(r_value) FROM ratings WHERE r_snippet=? AND r_value=3 OR r_value=2");
$stmt2 = $conn->prepare("SELECT COUNT(c_id) FROM comments WHERE c_snippet=?");
foreach ($snippets as $snippet){
$s_id = $snippet['s_id'];
$s_thumb = $snippet['s_thumb'];
$stmt1->bind_param("i",$s_id);
$stmt1->execute();
$stmt1->bind_result($numLikes);
$stmt1->fetch();
$stmt2->bind_param("i",$s_id);
$stmt2->execute();
$stmt2->bind_result($numComments);
$stmt2->fetch();
?>
** HTML here **
<?php
}
$stmt1->close();
$stmt2->close();
?>
$numLikes
工作正常,但$numComments
似乎返回NULL(从var_dump
),我不知道为什么。在phpMyAdmin的SQL工作正常,返回评论数...
后最少的代码,请与硬编码值替换bind_param。另外,把一个查询和检查错误:'printf(“错误:%s。\ n”,$ stmt1->错误);' – danihp
'错误:试图读取一行,而没有关联的结果集声明。' – frosty