表中有列:
friends: id | id1 | id2 | accepted | notification
users: id | username | email | password
好友中的id1始终是好友请求的发送者,id2是他的好友。
$sql = "SELECT * FROM friends WHERE id1='$id' AND accepted=1 AND notification=1;";
$result = mysqli_query($conn, $sql);
$data = mysqli_fetch_all($result, MYSQLI_ASSOC);
header("Content-Type: application/json");
echo json_encode($data);
$id 取自 session 。我想从 id(in users)=id2(如果是 friend )的用户那里获取用户名
$sql 会是什么样子?
最佳答案
不确定您想在逻辑上实现什么目标。 这意味着什么:id(在用户中)= id2(如果是 friend )?你能用文字描述一下吗
也许这样的事情可以让您了解如何继续:
SELECT
sender.id1 as senderID,
u.username as senderUsername,
receiver.id1 as receiverID,
u.username as receiverUsername
FROM users u
INNER JOIN friends sender ON u.id = sender.id1
INNER JOIN friends receiver ON u.id = receiver.id2
WHERE sender.id1='$id'
AND receiver.accepted=1
AND receiver.notification=1;
关于php - SQL连接两个不同的表,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/55985906/