How to extract Json data from Mysql using php

Question

currently iam using the following code

  <?php

// simulates result of db query for categories
$categories = array();
$categories[] = array('id' => 1, 'parent_id' => 0, 'name' => 'root');
$categories[] = array('id' => 2, 'parent_id' => 1, 'name' => 'Compact Discs');
$categories[] = array('id' => 3, 'parent_id' => 1, 'name' => 'Concert Souvenirs');

// simulates result of db query for products
$products = array();
$products[] = array('id' => 1, 'category_id' => 2, 'sku' => 'CD001', 'price'=>15.00, 'name' => 'CD: Greatest Hits');
$products[] = array('id' => 2, 'category_id' => 2, 'sku' => 'CD002', 'price'=>15.00, 'name' => 'CD: Unplugged');
$products[] = array('id' => 3, 'category_id' => 2, 'sku' => 'CD003', 'price'=>15.00, 'name' => 'CD: World Tour');
$products[] = array('id' => 4, 'category_id' => 3, 'sku' => 'PD001', 'price'=>10.00, 'name' => 'Souvenir Pin');
$products[] = array('id' => 5, 'category_id' => 3, 'sku' => 'PD002', 'price'=>10.00, 'name' => 'Mug');
$products[] = array('id' => 6, 'category_id' => 3, 'sku' => 'PD003', 'price'=>20.00, 'name' => 'Hat');
$products[] = array('id' => 7, 'category_id' => 3, 'sku' => 'PD004', 'price'=>12.00, 'name' => 'Summer Tour Poster');
$products[] = array('id' => 8, 'category_id' => 3, 'sku' => 'PD005', 'price'=>5.00,  'name' => 'Concert Program');

// create the response
$response = array('categories' => $categories, 'products' => $products);

// display the json encoded response
echo json_encode($response);

an the output json result is like this

{"categories":[{"id":1,"parent_id":0,"name":"root"},{"id":2,"parent_id":1,"name":"Compact Discs"},{"id":3,"parent_id":1,"name":"Concert Souvenirs"}],"products":[{"id":1,"category_id":2,"sku":"CD001","price":15,"name":"CD: Greatest Hits"},{"id":2,"category_id":2,"sku":"CD002","price":15,"name":"CD: Unplugged"},{"id":3,"category_id":2,"sku":"CD003","price":15,"name":"CD: World Tour"},{"id":4,"category_id":3,"sku":"PD001","price":10,"name":"Souvenir Pin"},{"id":5,"category_id":3,"sku":"PD002","price":10,"name":"Mug"},{"id":6,"category_id":3,"sku":"PD003","price":20,"name":"Hat"},{"id":7,"category_id":3,"sku":"PD004","price":12,"name":"Summer Tour Poster"},{"id":8,"category_id":3,"sku":"PD005","price":5,"name":"Concert Program"}]}

But, i want the same Json outputfrom PHP using Mysql. My database structure is like,

category

id | parent_id | name |

Products

id | category_id | sku | price | name |

how should i write my php code so that I will get data from Mysql and take the json result like above ? Thanks in Advance.

Answer 1

I guess the clearest way would be to "convert" your sql result sets to the same structures you're already using - arrays. This way you won't have to change anything else - the rest of the algorithm will work as is. So simply fetch the result rows to same structure arrays as you used for simulation.

Answer 2

The way you approach it seems fine to me

Example snippet

$result = Array( 'Categories' => Array(), 'Products' => Array());

$stmt = $mysqli->prepare( 'SELECT id, parent_id, name FROM category' );
$stmt->bind_result( $id, $parent_id, $name );
$stmt->execute();
while( $stmt->fetch() ) {
  $result['Categories'][] = Array( 'id' => $id, 'parent_id' => $parent_id, 'name' => $name );
} 
$stmt->close();
//Do the same for the other one

$jsonstring = json_encode( $result );

From there you should be able to figure it out yourself