连续打印同一张表中的不同数据

Question

Hi i want print differt data from same table with PHP. My table is:

Table A:
     ID    name
-----------
     111    Giovanna
     111    Jenny
     112    John
     113    Rick

I want this output:

Mansioni: 111   People:Giovanna,Jenny
          112   People:John
          113   People:Rick

My code php:

$codice=$_GET['id'];  //id is is chosen by the user
$query1="select distinct ID from A where ID= '".$codice."'";
$query2="select distinct name from A where ID= '".$codice."'";
$query_imp = pg_query($conn1, $query1);
$query_impiegati = pg_query($conn1, $query2);
    echo 'Mansioni: ';
        while($row1 = pg_fetch_array($query_imp)){
        while($row2 = pg_fetch_array($query_impiegati)){ ;
            echo '</table>';
                echo '<tr>
                <td>'.$row1['ID'].' 
                 &nbsp;&nbsp;&nbsp;&nbsp;People:'.$row2['name'].'<br></td> 
                </tr>';
                echo '</table>';
                }
            
}

My code don't work.How can i do?

Answer 1

A SQL result will almost always be a 2D array, so you need to do a "post-processing" after the request to transform your data. The idea is to use a associative array as dictionary.

/* 
  the SQL request will give your an array like : 
  [
    ['ID' => 111, 'name' => 'Giovanna'],
    ['ID' => 111, 'name' => 'Jenny'],
    ['ID' => 112, 'name' => 'John'],
    ['ID' => 113, 'name' => 'Rick']
  ]

  you want to transform it to something like :
  [
    '111' => ['Giovanna', 'Jenny'],
    '112' => ['John'],
    '113' => ['Rick']
  ]
*/

$codice=$_GET['id'];  //id is is chosen by the user
$query="select ID, name from A where ID= '".$codice."'";
$query_imp = pg_query($conn1, $query);
$dataById = [];
while($row = pg_fetch_array($query_imp)) {
  /* loop on each row */
  if(empty($dataById[$row['ID']) {
     /* if the entry of the dictionary is empty, initialize a empty array
     $dataById[$row['ID'] = [];
  }
  /* add the current name to the right entry */
  $dataById[$row['ID'][] = $row['name'];  
}

/* Text Rending */
foreach($dataById as $id) {
    echo $id . "     People:" . implode(',', $dataById[$id]);
}

I'm using an associative array to classify your data based on the ID. And impode to transform an array to a string.

Beware of the us of concatenation in SQL query: it's absolutely forbidden in production due to security breach. Search for "SQL injection".