使用php从while循环语句中的不同表中获取值

Question

I'm having an issue of retrieving values from two different tables. Here's the code so far:

$result = mysqli_query($conn,"SELECT * FROM articles");
$num = mysqli_num_rows($result);

while ($row = mysqli_fetch_array($result)) {
    $uid=$row['_uid'];

    $result2 = mysqli_query($conn, "SELECT _username FROM users WHERE _id = '$uid' ";
    $num2 = mysqli_num_rows($result2);

    while ($row2 = mysqli_fetch_array($result2)) {
        $username = $row2['_username'];
    }
    $divtext='<h3>'.$row['_posttype'].'</h3> <h2>'.$username.' </h2>';
}    

I've been reading that I should preform this while inside a while with multiple query, also found on w3 that you could directly assign a value to a variable directly using:

"SELECT _username INTO $username FROM users WHERE  _id = '$uid'  LIMIT 1";    

But this works in SQL inside myadmin, in a php I can't find how to cast it. I have also replace the fetch_row for fetch_assoc and still nothing, im struggling for two days already with this.

Answer 1

you could select al the value using a single query

SELECT a._uid , a._posttype, u._username 
FROM articles a
INNER JOIN users u on a._uid = u._id 

..

$result = mysqli_query($conn,
  "SELECT a._uid , a._posttype, u._username 
  FROM articles a
  INNER JOIN users u on a._uid = u._id");
$num = mysqli_num_rows($result);

while ($row = mysqli_fetch_array($result)) {

    $divtext='<h3>'.$row['_posttype'].'</h3> <h2>'.$username.' </h2>';

}  

$echo $divtext;