我有一个包含net_amount字段和last_updated_time字段的事务表,其中last_updated_time存储为毫秒.我需要使用月,年或日期来获得总金额组.我怎么能在PostgreSQL中做到这一点？
我的表如下所示:
+------------+-------------------+
| net_amount | last_updated_time |
+------------+-------------------+
| 100 | 1470286872831 |
+------------+-------------------+
| 200 | 1471594713801 |
+------------+-------------------+
| 300 | 1471594651335 |
+------------+-------------------+
期待结果如下:
+----------+---------------+
| month | sum_of_amount |
+----------+---------------+
| january | 1000 |
+----------+---------------+
| february | 2000 |
+----------+---------------+
| --- | ---- |
+----------+---------------+