将转储应用到结果时，LINQPad 抛出异常“TruncateTime(System.Nullable`1[System.DateTime])' has no supported translation to SQL”

Question

I have a Linq query done in LINQPad. This query has some froms, joins and a where clause (neither group by nor order by are used).

In where clause I am using below function to remove time from a DateTime field:

System.Data.Entity.DbFunctions.TruncateTime(myField)

This query return the results into a:

IQueryable<MyCustomClass>

When I execute query from LINQPad it is executed correctly without errors, but If I perform results.Dump() or results.ToList().Dump() in order to view the results in LINQPad I get below error:

TruncateTime(System.Nullable`1[System.DateTime])' has no supported translation to SQL.'

Answer 1

This is not LinqPad specific.

This basically means that the Where clause contains some conditions that can not be successfully translated from Linq to SQL.

In order to get around this you can split the where clause:

First part of the where clause contains all the SQL compatible operations, then add a .ToList() which will retrieve the data from the database, then finish with the non-SQL, but Linq to Object compatible part of the where clause.

I realize this will cause a greater pull from the database, but that is the limitation.