我目前正在使用 MySQL 创建一个将返回以下内容的 View :
NAME | EMAIL | LAST_SEEN
abby | a@l.d | 2015-10-31 14:36:26
abby | a@l.d | 2015-11-28 13:30:37
然后我将 GROUP BY name
应用于 select query
并返回以下内容
NAME | EMAIL | LAST_SEEN
abby | a@l.d | 2015-10-31 14:36:26
我想知道如何修复此查询,使其返回以下内容:
NAME | EMAIL | LAST_SEEN
abby | a@l.d | 2015-11-28 13:30:37
实际代码如下:
CREATE VIEW v_user_last_seen
AS
SELECT concat_ws(' ', u.first_name, u.middle_name, u.last_name) AS user_name
,c.email
,l.in_when AS last_seen
FROM user AS u
INNER JOIN check_here_first AS c ON c.email = u.email
INNER JOIN log AS l ON l.u_id = c.username
GROUP BY user_name
ORDER BY user_name ASC
最佳答案
只需使用 max(last_seen)
select name, email, max(last_seen)
from yourtable,
group by name, email;
关于php - 如何按列名分组并确保查询检索到最后更新,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/33984726/