似乎
正在发生的事情是$result_tag只保存检索到的sql数据的第一行。
当我在 SQl 上运行结果查询时，返回一个包含多行的表。但是，当我var_dump（）它时，它只返回第一行，没有其他任何内容。
while($row = $results->fetch_array(MYSQLI_BOTH)) {
echo ....stuff that dont matter
//Now I want some SQL results based on a result from ^^^ $row['ID']
$result = $conn->query("SELECT tags.Tag FROM tags WHERE tags.results_ID =".$row['ID'] );
$result_tag = $result->fetch_array(MYSQLI_NUM);
//I got the results. Now I want to compare them to another array '$explode'
//and echo out elements that are the same
foreach($explode as $explodeValue){
foreach($result_tag as $tag){
if($tag == $explodeValue){
echo $explodeValue;
}
}
}
}//end of 1st while
你想使用fetch_all(); fetch_array()只返回一行（作为数组）见 http://php.net/manual/en/mysqli-result.fetch-all.php
这实际上是最外面的人正在做的事情，一次获取一行fetch_array()
更改为
$result = $conn->query("SELECT * FROM tags WHERE results_ID =".$row['ID'] );