Question

我有一张这样的表：

.--------------------------------.
| Name  | XX | Date              |
.--------------------------------.
| N1    | 5  | 2009-05-01        |
| N1    | 10 | 2008-01-08        |
| N2    | 8  | 2009-02-02        |
.________________________________.

我的结果应该是这样的：

.------------.
| Name  | XX |
.------------.
| N1    | 5  |
| N2    | 8  |
.____________.

我只想要按名称分组的行，但只需要最新的行。我不希望在这个例子中XX = 10的行因为日期2009-05-01＆gt; 2008-01-08

我不知道如何按日期排序并将其分组:(

Answer 1

您想要分组的内容是什么？

select Name, XX
  from yourTable t1
 where Date = (select MAX(Date)
                 from yourTable t2
                where t1.Name = t2.Name)

如果您需要在最后一天汇总XX，那么：

select Name, SUM(XX)
  from yourTable t1
 where Date = (select MAX(Date)
                 from yourTable t2
                where t1.Name = t2.Name)
 group by Name

Answer 2

SELECT Name, XX FROM myTable GROUP BY Name ORDER BY Date DESC

您可能需要在日期字段周围加上引号

`Date`

Answer 3

很抱歉，但这两个都错了。

你应该

SELECT Name, XX
 FROM t1
 JOIN (SELECT Name, max(date)
        FROM t1
        GROUP BY Name) subquery
   ON t1.Name = subquery.Name AND t1.Date = subquery.Date

mysql查询与group by和order by

3 个答案: