sql查詢按月的天分組

Question

我有一個記錄表，其中包含創建的行的日期。 （Oracle數據庫）

ID    City       CreateDate
1     city-1     12.12.2017
1     city-2     13.12.2017
1     city-1     13.12.2017
1     city-3     12.12.2017
....
....

我想在一個月內創建一份每日報告。 例如12月天數的City-1報告

Day    Count
1      10
2      80
3      60
4      10
...
30     11

Answer 1

我認為您可以將提取與計數功能一起使用：

SELECT EXTRACT(day FROM CreateDate) "Day",
      COUNT(CreateDate) "Number of Reports"
      FROM yourTableName
      GROUP BY EXTRACT(day FROM CreateDate)
      ORDER BY "Number of Reports" ASC;

Answer 2

如果我正確理解，以下查詢將生成您想要的12月份的報告。

SELECT EXTRACT(day FROM CreateDate) "Day", COUNT(*) "Count" FROM your_record_table WHERE EXTRACT(month FROM CreateDate) = 12 GROUP BY EXTRACT(day FROM CreateDate) ORDER BY EXTRACT(day FROM CreateDate);