c# - Union with System.Linq.IQueryable get errors -

i trying use union follows :

var query1 = c in dc.hotel_meals_tbls              c.chdlunch != "0" && c.chdlunch != ""              select new              {                  service_code = c.hotelcodeid,                  service_name = c.hotelname,                  room_category = "",                  room_type = "",                  variance_name = "childlunch",                  market = "ww",                  contract_business_year = "2014/2015",                  contract_start_date = "01/11/2014",                  contract_end_date = "30/10/2015",                  type = "child policy",                  currency = c.currencycode,                  period_name = "",                  period_start_date = "",                  period_end_date = "",                  price = c.lunch,                  percentage = c.chdlunch + "%",                  num_to_stay = "",                  num_to_pay = "",                  penalty_time_limit = "",                  penalty_no_day_before = "",                  child_reference = "",                  text = c.childpolicy              }; var query2 = c in dc.hotel_meals_tbls              d in dc.hotelperiod_tbls              f in dc.hotelroom_tbls              c.hotelcodeid == d.hotelcodeid && c.hotelcodeid == f.hotelcodeid && f.dbl_highseason != 0 && d.periodname == "high"              select new              {                  service_code = c.hotelcodeid,                  service_name = c.hotelname,                  room_category = f.roomname,                  room_type = "dbl",                  variance_name = "",                  market = "ww",                  contract_business_year = "2014/2015",                  contract_start_date = "01/11/2014",                  contract_end_date = "30/10/2015",                  type = "cost",                  currency = c.currencycode,                  period_name = d.periodname,                  period_start_date = d._from,                  period_end_date = d._to,                  price = f.sgl_lowseason,                  percentage = "",                  num_to_stay = "",                  num_to_pay = "",                  penalty_time_limit = "",                  penalty_no_day_before = "",                  child_reference = "",                  text = ""              };  var result = query1.union(query2); 

and got errors:

'system.linq.iqueryable<anonymoustype#1>' not contain definition 'union' , best extension method overload 'system.linq.parallelenumerable.union<tsource>(system.linq.parallelquery<tsource>, system.collections.generic.ienumerable<tsource>)' has invalid arguments

instance argument: cannot convert 'system.linq.iqueryable<anonymoustype#1>' 'system.linq.parallelquery<anonymoustype#2>'

truly used method many times without errors...do have idea wrong in query?

the error message indicates .net thinks 2 anonymous types different. in order 2 anonymous types same must have same number of properties same names , types. i've gone through property list , appear have same names in same order. however, it's possible you've got different types in these areas:

type 1

period_start_date = "" period_end_date = "" price = c.lunch, text = c.childpolicy 

type 2

period_start_date = d._from period_end_date = d._to price = f.sgl_lowseason text = "" 

make sure d._from, d._to, , c.childpolicy strings , c.lunch , f.sgl_lowseason same type (e.g. maybe 1 int , other decimal).