如何从数据库中按月或年搜索/过滤

Question

I want to filter the report based on month or year using dropdown search button. I'm having problem because the data for month that being search cannot be displayed.

Here are some codes that I've tried:

if(!empty($_POST['search'])){
  $sql = "SELECT * FROM complain
        WHERE MONTH(timeComplain)='".$_POST['search']."'";
  $query = $conn -> query($sql);
  $row = $query -> fetch_assoc();
}

<form action="report.php" method="post">
  <div class="w3-left">
    <select name="search" class="w3-select" value="">
        <option value=""></option>
        <option value="1">January</option>
        <option value="2">February</option>
        <option value="3">March</option>
        <option value="4">April</option>
        <option value="5">May</option>
        <option value="6">June</option>
        <option value="7">July</option>
        <option value="8">August</option>
        <option value="9">September</option>
        <option value="10">October</option>
        <option value="11">November</option>
        <option value="12">December</option>
    </select>
   <input type="submit" id="search" value="Filter">              
  </div>
</form>

Answer 1

You forgot to execute the query.
Use PDO instead.
Your PHP code should look like this:

if(!empty($_POST['search'])){
  $sql = "SELECT * FROM complain WHERE MONTH(timeComplain)= :month";
  $query = $conn->prepare($sql);
  $params = array(':month' => $_POST['search']);
  $query->execute($params);
  $row = $query->fetch();
  // then you can do "echo $row['']"
}

You should execute the query before any results are received.
Your $conn should look like this:

$options = array(PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES utf8'); 

try { $conn = new PDO("mysql:host={$host};dbname={$dbname};charset=utf8", 
$username, $password, $options); } 
catch(PDOException $ex){ die("Failed to connect to the database: " . $ex->getMessage());} 
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); 
$conn->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);