如何获取MySQL数据库中的最新日期和最频繁出现的值

Question

如何获取MySQL数据库中的最新日期和最频繁出现的值？

我有以下数据库：

+----+---------+---------+-----------------------+--------+------------+---------+
| id | Name    | idStore | Name                  | idItem | date       | price   |
+----+---------+---------+-----------------------+--------+------------+---------+
| 1  | walmart |       1 | Red Delicious Apples  |      1 | 2011-10-28 | 0.93000 |
| 2  | walmart |       1 | Red Delicious Apples  |      1 | 2011-10-28 | 0.98000 |
| 3  | walmart |       1 | Red Delicious Apples  |      1 | 2011-10-29 | 0.90000 |
| 4  | walmart |       1 | Red Delicious Apples  |      1 | 2011-10-29 | 0.91000 |
| 5  | walmart |       1 | Red Delicious Apples  |      1 | 2011-10-29 | 0.92000 |
| 6  | walmart |       1 | Red Delicious Apples  |      1 | 2011-10-29 | 0.92000 |
| 7  | walmart |       1 | Red Delicious Apples  |      1 | 2011-10-29 | 0.92000 |
| 8  | walmart |       1 | Red Delicious Apples  |      1 | 2011-10-29 | 0.93000 |
| 9  | walmart |       1 | Red Delicious Apples  |      1 | 2011-10-28 | 0.93000 |
| 10 | walmart |       1 | Red Delicious Apples  |      1 | 2011-10-28 | 0.94000 |
| 11 | walmart |       1 | Red Delicious Apples  |      1 | 2011-10-28 | 0.94000 |
| 12 | walmart |       1 | Red Delicious Apples  |      1 | 2011-10-28 | 0.94000 |
| 13 | walmart |       1 | Red Delicious Apples  |      1 | 2011-10-28 | 0.94000 |
| 14 | walmart |       1 | Red Delicious Apples  |      1 | 2011-10-28 | 0.94000 |
| 15 | walmart |       1 | Red Delicious Apples  |      1 | 2011-10-12 | 0.98000 |
| 16 | walmart |       1 | Honeycrisp Apples     |      2 | 2011-10-22 | 1.98000 |
| 17 | walmart |       1 | Sonya Apples          |      3 | 2011-10-22 | 2.88000 |
| 18 | walmart |       1 | Gold Delicious Apples |      4 | 2011-10-22 | 0.98000 |
| 19 | walmart |       1 | Sweet Tango Apples    |      5 | 2011-10-22 | 2.48000 |
| 20 | walmart |       1 | Granny Smith Apples   |      6 | 2011-10-22 | 1.28000 |
| 21 | walmart |       1 | Fugi Apples           |      7 | 2011-10-22 | 1.38000 |
+----+---------+---------+-----------------------+--------+------------+---------+

我想得到以下结果：

+----+---------+---------+-----------------------+--------+------------+---------+
| id | Name    | idStore | Name                  | idItem | date       | price   |
+----+---------+---------+-----------------------+--------+------------+---------+
| 5  | walmart |       1 | Red Delicious Apples  |      1 | 2011-10-29 | 0.92000 |
| 16 | walmart |       1 | Honeycrisp Apples     |      2 | 2011-10-22 | 1.98000 |
| 17 | walmart |       1 | Sonya Apples          |      3 | 2011-10-22 | 2.88000 |
| 18 | walmart |       1 | Gold Delicious Apples |      4 | 2011-10-22 | 0.98000 |
| 19 | walmart |       1 | Sweet Tango Apples    |      5 | 2011-10-22 | 2.48000 |
| 20 | walmart |       1 | Granny Smith Apples   |      6 | 2011-10-22 | 1.28000 |
| 21 | walmart |       1 | Fugi Apples           |      7 | 2011-10-22 | 1.38000 |
+----+---------+---------+-----------------------+--------+------------+---------+

我使用以下查询，但它不起作用，因为它为我提供了所有具有最新日期的项目

select id, store_name as Name, idStore, Name, idItem , max(Price.date), min(Price.price) From table group by idStore, Store.Name, idItem, Item.Name, price ORDER BY idItem ASC, date DESC;

我从分组中删除了价格并获得了最低价格（不是最常出现的价格）

select id, store_name as Name, idStore, Name, idItem , max(Price.date), min(Price.price) From table group by idStore, Store.Name, idItem, Item.Name ORDER BY idItem ASC, date DESC;

我很难解决这个问题。 谢谢！

Answer 1

您必须使用子查询，这是优化您的请求的最佳方法：

您第一次选择max（date），第二次再次选择价格

Answer 2

尝试这个

创建表#temp（从名称的tblname组中选择max（date），Name）

然后在#temp表上进行全表扫描，并从tblname中获取ID，其中

temp.date = tblname.date和＃temp.name = tblname.date