获取特定时间范围和特定条目类型的值的平均值

I have a table like this:

我有这样一张桌子：

ID | Type | Value | Timestamp
--------------------------------
 1  | AAA  | 0.5   | day 1 hour 1
 2  | BBB  | 1.5   | day 1 hour 1
 3  | CCC  | 1.8   | day 1 hour 1
.....
11  | AAA  | 0.6   | day 1 hour 2
12  | BBB  | 1.4   | day 1 hour 2
13  | CCC  | 1.5   | day 1 hour 2
.....


ID := Int, PK, AI, and so on
Type := String/Varchar
Value := Double
Timestamp := Unix Timestamp (Int), could be easily changed to date type
ID | Ty