c# - How to solve issue "Could not translate expression ...into SQL and could not treat it as a local expression." -

this question has answer here:

• linq “could not translate expression… sql , not treat local expression.” 3 answers

i have code below:

void main() {     var q = in applicants              where(a.claims.any())              select a.claims.sum(c => c.totalclaimamount());       q.dump(); }  public static class myext {     public static decimal totalclaimamount(this claim c)     {         var t = c.accommodations.sum(a => a.amountclaimed) +                 c.mealallowances.sum(ma => ma.amountclaimed) +                 c.meals.sum(m => m.amountclaimed) +                 c.mileages.sum(mi => mi.amountclaimed) +                 c.others.sum(o => o.amountclaimed) +                 c.parkingtransits.sum(pt => pt.amountclaimed) +                 c.travels.sum(tr => tr.amountclaimed);          return (decimal)t;     } } 

when run in linqpad below issue:

invalidoperationexception: not translate expression 'a.claims.sum(c => c.totalclaimamount())' sql , not treat local expression.

please me out. many thanks

there no corresponding command custom method in sql. compiler not translate expression. instead first items,then select results:

 var items = applicants.where(a => a.claims.any()).tolist();  var results = items.select(a => a.claims.sum(c => c.totalclaimamount());