在日期字段中按月分組（字符串）

Question

帶有存儲日期的字符串字段的表（不建議我更改字段類型，這會造成危險）。

+--+----------+------+
|id|date      |amount|
+--+----------+------+
|1 |23-03-2014|5000  |
+--+----------+------+
|2 |25-03-2014|3000  |
+--+----------+------+
|3 |21-04-2014|3000  |
+--+----------+------+
|4 |25-04-2014|4000  |
+--+----------+------+

我想編寫一個模型函數，該函數將返回表中按月分組的金額之和。 我該怎么辦？ 它將顯示如下輸出

03 - 8000
04 - 7000

Answer 1

SELECT MONTH(date_field) as mon, SUM(amount) as total FROM table_name GROUP BY MONTH(date_field);

更新：

SELECT SUBSTR(date_field,6,2) as mon, SUM(amount) as total FROM table_name GROUP BY mon;

Answer 2

您可以嘗試以下查詢

SELECT SUM(amount) FROM table GROUP BY MONTH(date)

Answer 3

試試MONTH（）

SELECT MONTH(date),SUM(amount) FROM table GROUP BY MONTH(date)