[TABLE1]
cardid     total
------------------
1          24.5
4          21
3          12.4
1          45
2          47
6          58.2
2          45.1[TABLE2]
cardid     typeid 
-------------------
1          1
2          2
3          3
4          1
5          2
6          1[TABLE3]
typeid     typename
--------------------
1          贵宾卡
2          金卡
3          银卡想得到如下记录集
typename   mysum
-----------------
贵宾卡     107.3
金卡       92.1
银卡       12.4怎么写SQL语句啊,多谢各位!