Showing a message when no data found in SQL

Question

I'm trying to show a "Data not Found" message when query result is empty.

For example, if I have the following invoice IDs in a database:

 11
 12
 13

when user inputs invoice 11, show the data. But when user input 14 data show "data not found".

I have tried the following, but it doesn't work

if ( $SQLshow = '' ) {
    echo 'No data found in database!';
}

this my full code

<table>   
  <tbody>
                    <?php
                    $username = $_COOKIE['usernameloc'];
                    $invoice = $_GET['invoice'];
                    $SQLshow = mysqli_query($con,"
    SELECT * 
      FROM datapo 
     where username = '$username' 
       and Invoice_Number = '$invoice' 
     ORDER 
        BY id DESC 
     limit $offset
         , $dataperPage
    ");
                    $noUrut = 1;
                    while($row = mysqli_fetch_array($SQLshow)){
                    ?>
                    <div>
                    <tr>            
                        <td><?php echo $row[id]; ?></td>                        
                        <td><?php echo $row[Request_Date]; ?></td>              
                        <td><?php echo $row[Partner]; ?></td>                       
                        <td><?php echo $row[Package]; ?></td>
                    </tr>
                    <?php 
                    $noUrut++;
                    }


                    if ( $SQLshow = '' ) {
                       echo 'No data found in database!';
                    }


                    ?>
                </div>
 </tbody>
</table>

Answer 1

You can use num_row which returns the number of Rows:

if($query->num_rows){
 while($row = mysqli_fetch_assoc($query){
  echo 'row';
 }
}else{
 echo 'no result';
}