我有一个mysql表,其中“ meeting_id”是一个列。我只需要在表POLLS上显示与此会议ID相关的结果
实际查询是:
$stmt = $pdo->prepare('SELECT p.*, GROUP_CONCAT(pa.title ORDER BY pa.id) AS answers
FROM polls p
LEFT JOIN poll_answers pa ON pa.poll_id = p.id
GROUP BY p.id');
我尝试过但没有成功:
$stmt = $pdo->prepare('SELECT p.*, GROUP_CONCAT(pa.title WHERE meeting_id = '.$meeting_id.' ORDER BY pa.id) AS answers
FROM polls p
LEFT JOIN poll_answers pa ON pa.poll_id = p.id
GROUP BY p.id');
谢谢你们
WHERE子句不在内部GROUP_CONCAT()
,它在FROM
和之后JOIN
。
您还应该使用参数,而不是变量串联。
$stmt = $pdo->prepare('SELECT p.*, GROUP_CONCAT(pa.title ORDER BY pa.id) AS answers
FROM polls p
LEFT JOIN poll_answers pa ON pa.poll_id = p.id
WHERE p.meeting_id = :meeting_id
GROUP BY p.id');
$stmt->bindParam(':meeting_id', $meeting_id);
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