php mysqli_fetch_array() 期望参数 1 是 mysqli_result，null 给定
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mysqli_fetch_array() expects parameter 1 to be mysqli_result, null given
提问by Mike_C
I'm getting an error that says "mysqli_fetch_array() expects parameter 1 to be mysqli_result, null given" but everything looks good. What am I missing or adding here? It says the error is in Line 41. I appreciate you looking into this -- it's driving me crazy!
我收到一条错误消息，指出“mysqli_fetch_array() 期望参数 1 为 mysqli_result，给出 null”，但一切看起来都不错。我在这里缺少什么或添加了什么？它说错误在第 41 行。感谢您对此进行调查——这让我发疯！
<html>
<head>
<title>Search</title>
</head>
<body>
<h1>Search</h1>
<form method="post" action="search.php">
<input type="hidden" name="submitted" value="true" />
<label> Search | Category:
<select name="category">
<option value="name">Name</option>
<option value="date">Date</option>
</select>
</label>
<label>Search Criteria: <input type="text" name="criteria" /></label>
<input type="submit" />
</form>
<?php
if (isset($_POST['submitted'])) {
// connect to DB
include('connect.php');
$category = $_POST['category'];
$criteria = $_POST['criteria'];
$query = "SELECT * FROM calls WHERE $category = '$category'";
$result = mysqli_query ($dbcon, $query) or die ('Error');
echo "<table>";
echo "<tr> <th>Date</th> <th>Name</th>";
}
while ($row = mysqli_fetch_array($result, MYSQLI_ASSOC)) {
echo "<tr><td>";
echo $row ['date'];
echo "<tr><td>";
echo $row ['name'];
}
?>
</body>
</html>
回答by Bryan Elliott
You have a "$" in your query..
您的查询中有一个“$”。
Should be:
应该：
SELECT * FROM calls WHERE category = '$category'
回答by apartridge
Proper indentation of your code will give you an indication of your problem. Notice that you do
代码的适当缩进将指示您的问题。注意你做
$result = mysqli_query ($dbcon, $query) or die ('Error');
Inside
里面
if (isset($_POST['submitted'])) {
However,
然而，
while ($row = mysqli_fetch_array($result, MYSQLI_ASSOC)) {
is done outside this if-block (where $resultis null). Move the }down so it also contains the while.
在此 if 块之外完成（其中$result是null）。}向下移动使其也包含while.
Also, you have a syntax error in your SQL query which will become apparent when you fix this first issue.
此外，您的 SQL 查询中存在语法错误，当您解决第一个问题时，该错误会变得很明显。
