带有条件语句的mysqli fetch_assoc

Question

I am trying to display multiple parts of a query on my page using fetch_assoc and some conditional statements. My first while loop is displaying the correct information, but loops 2 and 3 are not displaying any information. What would be the correct way to filter my results?

require_once('inc/connection.inc.php');

//create database connection
$conn = dbConnect();

//create SQL
$sql = 'SELECT * FROM menu';

$result = $conn->query($sql) or die(mysqli_error());

while($row = $result->fetch_assoc()){

if($row['category'] == 'appetizers'){ 
    echo $row['title']; 
    echo $row['price'];
}  

}

while($row = $result->fetch_assoc()){

if($row['category'] == 'salads'){ 
    echo $row['title']; 
    echo $row['price'];
}  

}

while($row = $result->fetch_assoc()){

if($row['category'] == 'desserts'){ 
    echo $row['title']; 
    echo $row['price'];
}  

}

Answer 1

Why not do it like this:

while($row = $result->fetch_assoc()){

   if($row['category'] == 'appetizers'){ 
     echo '<h1>Appetizers</h1>';
     echo $row['title']; 
     echo $row['price'];
   }  

   if($row['category'] == 'salads'){ 
     echo '<h1>Salads</h1>';
     echo $row['title']; 
     echo $row['price'];
   }  

   if($row['category'] == 'desserts'){ 
     echo '<h1>Desserts</h1>';
     echo $row['title']; 
     echo $row['price'];
   } 

}

i.e., use the conditions in a single while loop.

OR

You can use mysqli_data_seek to reset the pointer to the first record and re-use the same resource multiple times

while($row = $result->fetch_assoc()){

   if($row['category'] == 'appetizers'){ 
     echo $row['title']; 
     echo $row['price'];
   }  
}

mysqli_data_seek($result,0);
while($row = $result->fetch_assoc()){

   if($row['category'] == 'salads'){ 
     echo $row['title']; 
     echo $row['price'];
   }
}

mysqli_data_seek($result,0);
while($row = $result->fetch_assoc()){

   if($row['category'] == 'desserts'){ 
     echo $row['title']; 
     echo $row['price'];
   }
}