我想你的意思是从表post和pcgames中获取数据，并带有分类条件。如果你想这么做。在您的php上尝试以下操作：

<?php
    $game = $_GET['game'];
    $ids = mysqli_real_escape_string($conDB,$id);
    $no = 1;

    //this will be get data from post table
    $query = "SELECT * FROM `post` WHERE `category` ='" . $game . "'";
    $result = mysqli_query($conDB,$query); 

    //this will be get data from pcgames table
    $query1 = "SELECT * FROM `pcgames` WHERE `category` ='" . $game . "'";
    $result1 = mysqli_query($conDB,$query1);       
?>
<table border=1>
    <tr>
        <th>No</th> <th>Category</th> <th>Game</th>
    </tr>
    <?php  
    //fetch data from post table
    while($user_data = mysqli_fetch_array($result)) {         
        echo "<td>".$no++."</td>";
        echo "<td>".$user_data['category']."</td>";
        echo "<td>".$user_data['game']."</td>";     
    }
    //fetch data from pcgames table
    while($user_data1 = mysqli_fetch_array($result1)) {         
        echo "<td>".$no++."</td>";
        echo "<td>".$user_data1['category']."</td>";
        echo "<td>".$user_data1['game']."</td>";     
    }
    ?>
</table>