SQL multiple sum by PARTITION - sql

Question

I have the following postgreSql table stock, there the structure is following
| column | pk |
+--------+-----+
| date | yes |
| id | yes |
| type | yes |
| qty | |
| fee | |
table looks like this
| date | id | type | qty | fee |
+------------+-----+------+------+------+
| 2015-01-01 | 001 | CB04 | 500 | 2 |
| 2015-01-01 | 002 | CB04 | 1500 | 3 |
| 2015-01-01 | 003 | CB04 | 500 | 1 |
| 2015-01-01 | 004 | CB04 | 100 | 5 |
| 2015-01-01 | 001 | CB02 | 800 | 6 |
| 2015-01-02 | 002 | CB03 | 3100 | 1 |
| | | | | |
I want to create a view or query, so that the result looks like this.
| date | type | t_qty | total_weighted_fee |
+------------+------+-------+--------------------+
| 2015-01-01 | CB04 | 2600 | 2.5 |
| 2015-01-01 | CB03 | 3100 | 1 |
| | | | |
what I did is this
http://sqlfiddle.com/#!17/39fb8a/18
But this is not the output what I want.
The Sub Query table looks like this:
% of total Qty = qty / t_qty
weighted fee = fee * % of total Qty
| date | id | type | qty | fee | t_qty | % of total Qty | weighted fee |
+------------+-----+------+------+-----+-------+----------------+--------------+
| 2015-01-01 | 001 | CB04 | 500 | 2 | 2600 | 0.19 | 0.38 |
| 2015-01-01 | 002 | CB04 | 1500 | 3 | 2600 | 0.58 | 1.73 |
| 2015-01-01 | 003 | CB04 | 500 | 1 | 2600 | 0.19 | 0.192 |
| 2015-01-01 | 004 | CB04 | 100 | 5 | 2600 | 0.04 | 0.192 |
| 2015-01-01 | 002 | CB03 | 3100 | 1 | 3100 | 1 | 1 |
| | | | | | | | |

Answer 1

You can use aggregation . . . I don't think you are far off:
select date, type, sum(qty),
sum(fee * qty * 1.0) / nullif(sum(qty), 0)
from t
group by date, type;