Class Method returns incorrect records.

This is the query I am running in DB:

 select UM.USER_NAME, RM.ROLE_ID, RM.ROLE_NAME
  FROM [MICommonDB].[dbo].[ROLE_USER_MAPPING] as RUM
  join [MICommonDB].[dbo].[ROLE_MASTER] as RM ON RM.ROLE_ID=RUM.ROLE_ID
  join [MICommonDB].[dbo].[USER_MASTER] UM ON UM.USER_ID = RUM.USER_ID
  where UM.USER_NAME='useruser'

which is giving me proper result(i.e., 2 records) when running in SQL server.

Now I have created below method in a class with same query (I am calling this method inside Controller):

public IEnumerable<RoleUserDO> getRoleNameByUserName(string userName)
        {
            IEnumerable<RoleUserDO> strResult = null;

            strResult = (from RUM in oDBContext.ROLE_USER_MAPPING
                         join RM in oDBContext.ROLE_MASTER on RUM.ROLE_ID equals RM.ROLE_ID
                         join UM in oDBContext.USER_MASTER on RUM.USER_ID equals UM.USER_ID

                         where UM.USER_NAME.Equals(userName)

                         select new RoleUserDO
                         {
                             //USER_NAME = UM.USER_NAME,
                             //ROLE_ID = RM.ROLE_ID,
                             ROLE_NAME = RM.ROLE_NAME

                         }).ToList();

            return strResult.AsQueryable();
        }

but it returns only 1 record instead of 2 records(when compared with DB query)

Please tell what is wrong in my method and why the return records are not matching with DB query records ?

Please note that I am new in C# asp.net MVC.