我有一个预约表,我需要选择为所有用户的最新记录,目前我的查询返回的最古老的每个用户ID,而不是最新的一个每个如何选择所有的最新记录所有用户的
委任表格
+-------+--------------+--------------+--------------+
| ID | time | userid | description |
+-------+--------------+--------------+--------------+
| 1 | 2017-10-20 | 4 | etc |
+-------+--------------+--------------+--------------+
| 2 | 2017-10-21 | 6 | etc |
+-------+--------------+--------------+--------------+
| 3 | 2017-10-22 | 7 | etc |
+-------+--------------+--------------+--------------+
| 4 | 2017-10-23 | 8 | etc |
+-------+--------------+--------------+--------------+
| 5 | 2017-10-24 | 6 | etc |
+-------+--------------+--------------+--------------+
| 6 | 2017-10-25 | 7 | etc |
+-------+--------------+--------------+--------------+
用户表
+-------+--------------+--------------+--------------+
| ID | first | last | status |
+-------+--------------+--------------+--------------+
| 4 | jo | do | 1 |
+-------+--------------+--------------+--------------+
| 6 | jid | did | 1 |
+-------+--------------+--------------+--------------+
| 7 | jone | done | 1 |
+-------+--------------+--------------+--------------+
| 8 | ja | da | 1 |
+-------+--------------+--------------+--------------+
当前查询
$sql = "SELECT *
FROM appointment
LEFT JOIN users AS user
ON user.id = appointment.userid
WHERE user.status = 1
GROUP BY appointment.userid
";
当前结果
+-------+--------------+--------------+--------------+
| ID | time | userid | description |
+-------+--------------+--------------+--------------+
| 1 | 2017-10-20 | 4 | etc |
+-------+--------------+--------------+--------------+
| 2 | 2017-10-21 | 6 | etc |
+-------+--------------+--------------+--------------+
| 3 | 2017-10-22 | 7 | etc |
+-------+--------------+--------------+--------------+
| 4 | 2017-10-23 | 8 | etc |
+-------+--------------+--------------+--------------+
预期输出
+-------+--------------+--------------+--------------+
| ID | time | userid | description |
+-------+--------------+--------------+--------------+
| 1 | 2017-10-20 | 4 | etc |
+-------+--------------+--------------+--------------+
| 4 | 2017-10-23 | 8 | etc |
+-------+--------------+--------------+--------------+
| 5 | 2017-10-24 | 6 | etc |
+-------+--------------+--------------+--------------+
| 6 | 2017-10-25 | 7 | etc |
+-------+--------------+--------------+--------------+
你有一组通过,但没有聚集函数.. – Randy