Unable to translate set operation when matching columns on both sides have different store types

Question

Unable to translate set operation when matching columns on both sides have different store types

权达罗 1

(
from item in _context.Table1
select new SomeModel
{
Name ="A"
}
)
.Union
(
from item in _context.Table2
select new SomeModel
{
Name = Convert.ToString(item.UserName)
}
)
it is not work,and throw out：Unable to translate set operation when matching columns on both sides have different store types.
Why?

Jack J Jun 25,306 Reputation points

2022-07-07T07:41:30.417+00:00

@权达罗 , Welcome to Microsoft Q&A, based on my test, I could not reproduce your problem even if I used the same code with you. However, I find the simliar issue in the stack overflow. You could add .AsEnumerable() for the first query before .Union may fix the issue.

Link:Can't process set operations after client evaluation efcore

1 answer

Your answer

Jack J Jun 25,306 Reputation points

2022-07-07T07:41:30.417+00:00

@权达罗 , Welcome to Microsoft Q&A, based on my test, I could not reproduce your problem even if I used the same code with you. However, I find the simliar issue in the stack overflow. You could add .AsEnumerable() for the first query before .Union may fix the issue.

Link:Can't process set operations after client evaluation efcore

Answer 1

Bruce (SqlWork.com) 83,986

the linq expression must be converted to sql. The Convert function is not supported. if using a late enough version .ToString() should work:

Name = item.UserName.ToString()

权达罗 1

version : .net 6+Microsoft.EntityFrameworkCore 6.0.6

i try ToString(),but ,not work:

  var qry1 = from a in UnitWork.Find<Table1>(null)  
                       select new  
                       {  
                           Name = "q",  
                           Id = a.Id,  
                       };  
            var qry2 = from b in UnitWork.Find<Table2>(null)  
                       select new  
                       {  
                           Name=b.Name.ToString(),  
                           Id=b.Id  
                       };  
            var list = qry1.Union(qry2).ToList();

throw:Unable to translate set operation after client projection has been applied. Consider moving the set operation before the last 'Select' call.

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Unable to translate set operation when matching columns on both sides have different store types

1 answer

Your answer