这个linq查询有什么问题，它显示了不包含'union'的定义的错误

(from rev in db.vM29s
          where Years.Contains(rev.FinancialYear) && rev.Exclude=="No"
          group rev by new { rev.RevenueCode, rev.FinancialYear } into g
 select new
 {
     Revenuecode = g.Key.RevenueCode,
     totalRevenue = g.Sum(x => x.RevenueAmount),
     RevenueEnglish = (from a in db.RevenueCodes where a._RevenueCode == g.Key.RevenueCode select a.RevenueEng).FirstOrDefault(),
     //  MinorCode = (from a in db.MinorCodes where a._MinorCode == g.Key.MinorCode select a.MinorEng),
     RevenueDari = (from a in db.RevenueCodes where a._RevenueCode == g.Key.RevenueCode select a.RevenueDari).FirstOrDefault(),
     Yearss = g.Key.FinancialYear
  }
)
.Union
(from u in db.rtastable
           where Years.Contains(u.Year)
           group u by new { u.objectcode, u.Year } into g
 select new
 {
     Revenuecode = g.Key.objectcode,
     totalRevenue = g.Sum(x => x.amount),
     RevenueEnglish = (from a in db.RevenueCodes where a._RevenueCode == g.Key.objectcode select a.RevenueEng).FirstOrDefault(),
     //  MinorCode = (from a in db.MinorCodes where a._MinorCode == g.Key.MinorCode select a.MinorEng),
     RevenueDari = (from a in db.RevenueCodes where a._RevenueCode == g.Key.objectcode select a.RevenueDari).FirstOrDefault(),
     Yearss = g.Key.Year
  }
)
.ToList();