sql server - SQL Overlapping Date Range -

i have table 3 fields "start date" , "end date" , "allocation %". need find out records in table falls within 3 months current date,

and (this 1 tricky) records overlapped date ranges sum(allocation %) > 100.

please me come query.

this table schema.

table (resourceassignment)    - resourceassignmentid (pk)    - resourceid (fk)    - assigned (fk)    - start date    - end date    - allocation % 

i need find on allocated resources within period (from current day 3 months).

thanks in advance!

not sure if you're after, show resourceid allocation above 100% begin or end date within last 3 months:

select resourceid  resourceassignment startdate between dateadd(month,-3,getdate())  , getdate()   or enddate between dateadd(month,-3,getdate())  , getdate() group resourceid  having sum([allocation %]) > 100