Hive 配置单元计数另一个表中匹配行的数目

表1：

表2：

| ID | Timestamp
| 1  | 1970
| 2  | 1971

我如何执行一个查询，以这样的方式连接表，从而获得：

| Timestamp |
| 1970      |
| 1970      |
| 1970      |
| 1971      |
| 1971      |

基本上，

在时间戳上加入

，但仅仅是为了得到一个计数

| ID | Timestamp | Count
| 1  | 1970      | 3
| 2  | 1971      | 2

---

---

select  t1.ID
       ,t1.`Timestamp`
       ,coalesce (t2.`Count`,0) as `Count`

from    Table1 t1

        left join  (select      `Timestamp`
                                ,count(*)    as `Count`
                    from        Table2
                    group by    `Timestamp`
                    ) t2

        on          t2.`Timestamp` = t1.`Timestamp`

+----+-----------+-------+
| id | timestamp | count |
+----+-----------+-------+
|  1 |      1970 |     3 |
|  2 |      1971 |     2 |
+----+-----------+-------+