MYSQL 查询与 html 输入

Question

Hello I am trying to create a query for a table that shows the performances performed by the artist selected in the form's drop down menu. I am receiving an undefined index error but I used the same piece of code to reference the input earlier in my code so I am confused. any help is appreciated.

Query error: Uncaught PDOException: SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'INNER JOIN performance p ON p.artist_id = a.artist_id INNER JOIN recording r ON' at line 4 in C:\inetpub\wwwroot\courses\354\Students\raw51419\final exam\test.php:72 Stack trace: #0 C:\inetpub\wwwroot\courses\354\Students\raw51419\final exam\test.php(72): PDO->prepare('\nSELECT a.first...') #1 {main} thrown in C:\inetpub\wwwroot\courses\354\Students\raw51419\final exam\test.php on line 72

    $content ="";
require_once("db.php");
$query = "
SELECT a.first_name, a.last_name, s.genre, s.title, s.year,r.length, p.venue, p.date
FROM artist a
WHERE artist_id = ?
INNER JOIN performance p ON p.artist_id = a.artist_id 
INNER JOIN recording r ON p.recording_id = r.recording_id
INNER JOIN song s ON p.song_id = s.song_id";
$stmt = $conn->prepare($query);
$stmt->execute([$artid]);
foreach ($stmt as $row) {

$content .=
  "<tr>
    <td>{$row["first_name"]}</td>
    <td>{$row["last_name"]}</td>
    <td>{$row["title"]}</td>
    <td>{$row["year"]}</td>
    <td>{$row["genre"]}</td>
    <td>{$row["date"]}</td>
    <td>{$row["venue"]}</td>
    <td>{$row["length"]}</td>
  </tr>";
  }

$content =
  "<table>
  <h4>Performances:</h4>
  <table class='table table-bordered table-striped'>
    <tr>
        <th>First</th>
        <th>Last</th>
        <th>Title</th>
        <th>Year</th>
        <th>Genre</th>
        <th>Date</th>
        <th>Venue</th>
        <th>Length</th>
    </tr>
    {$content}
    </table>";

Answer 1

The order of things in SELECT is strict. The common items are:

SELECT ...
FROM ...
JOIN ...   ON ...
WHERE ...
GROUP BY ...
HAVING ...
ORDER BY ...
LIMIT ...

Many of those clauses are optional.