如何在MySQL中为特定用户更新用户登录时间?
为此,将ORDER BY与LIMIT一起使用。让我们首先创建一个表,其中有一个包含用户ID,登录时间和名称的列-
mysql> create table DemoTable1911(
UserId int,
UserLoggedInTime time,
UserName varchar(20)
);
使用插入命令在表中插入一些记录-
mysql> insert into DemoTable1911 values(100,'7:32:00','Chris');mysql> insert into DemoTable1911 values(101,'5:00:00','David');
mysql> insert into DemoTable1911 values(102,'6:10:20','Mike');
mysql> insert into DemoTable1911 values(103,'3:55:00','Carol');
使用select语句显示表中的所有记录-
mysql> select * from DemoTable1911;
这将产生以下输出-
+--------+------------------+----------+| UserId | UserLoggedInTime | UserName |
+--------+------------------+----------+
| 100 | 07:32:00 | Chris |
| 101 | 05:00:00 | David |
| 102 | 06:10:20 | Mike |
| 103 | 03:55:00 | Carol |
+--------+------------------+----------+
4 rows in set (0.00 sec)
这是用于更新特定用户“ Carol”的登录时间的查询-
mysql> update DemoTable1911set UserLoggedInTime='12:30:45'
where UserName='Carol'
order by UserId DESC
Limit 1;
Rows matched: 1 Changed: 1 Warnings: 0
让我们再次检查表记录-
mysql> select * from DemoTable1911;
这将产生以下输出-
+--------+------------------+----------+| UserId | UserLoggedInTime | UserName |
+--------+------------------+----------+
| 100 | 07:32:00 | Chris |
| 101 | 05:00:00 | David |
| 102 | 06:10:20 | Mike |
| 103 | 12:30:45 | Carol |
+--------+------------------+----------+
4 rows in set (0.00 sec)
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