c# - Join + Group + Aggregate in LINQ -

i have following query, put datagrid:

var balanceperaccount = bal in data.balancedetails                         join acc in data.userpaymentdetails on bal.username equals acc.username                         bal.paymentid == 0                         group bal bal.username g                         g.sum(p => p.rebatebeforeservice) >= 20                         select new                         {                             username = g.key,                             amount = g.sum(p => p.rebatebeforeservice),                         }; dgpaymentspending.datasource = balanceperaccount; dgpaymentspending.databind(); 

what add inside acc in select. example add paymentprovider = acc.paymentprovider. tried flipping every way think of, including getting first() group , trying access there, can't seem find way access it. might missing simple, have been looking around google time , can't seem find comparable example. have idea?

extend grouping source using anonymous type: new { bal, acc } , use first

var balanceperaccount = bal in data.balancedetails                         join acc in data.userpaymentdetails on bal.username equals acc.username                         bal.paymentid == 0                         group new { bal, acc } bal.username g                         g.sum(p => p.bal.rebatebeforeservice) >= 20                         select new                         {                             username = g.key,                             paymentprovider = g.firstordefault().acc.paymentprovider,                             amount = g.sum(p => p.bal.rebatebeforeservice),                         };