oracle sqldeveloper - SQL create view with sum query -

oracle sqldeveloper - SQL create view with sum query -

i have next registration table

| emp_id | start_date | end_date | pnum | | 1 | 2014-10-20 | 2014-10-25| 10 | | 2 | 2014-10-20 | 2014-10-30| 30 |

and want next result in view

| start_date | end_date | totalnum | | 2014-10-20 | 2014-10-25| 40 | | 2014-10-20 | 2014-10-30| 40 |

and have tried create view sum query no success .

create view emp select start_date ,end_date,(select sum(pnum) s) totalnum s grouping [start_date],end_date

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