Mapper entities without foreign key

@acjh Good morning, I am working with the AuditLog entity. I want to implement a service that returns all the logs that have been generated, and that these come with the user who performed the action. When I use the repository with the GetAllInclude method I cannot link the user because it is not the entity’s foreign key. How can I return the mapped object with user information? I want to replace GetAll by GetAllInclude. My code

Service:

public async Task<PagedResultDto<AuditLogDto>> GetAllAudityLog(PagedAuditLogResultRequestDto input)
        {
           var query = _auditLogRepository.GetAll()
                .WhereIf(input.UserId > 0, t => t.UserId == input.UserId)
                .Take(input.MaxResultCount)
                .Skip(input.SkipCount);
            var auditLogs = await query.ToListAsync();

            return new PagedResultDto<AuditLogDto>
            {
                TotalCount = auditLogs.Count,
                Items = ObjectMapper.Map<List<AuditLogDto>>(auditLogs)
            };
        }

DTO:

[AutoMapFrom(typeof(AuditLog))]
   public class AuditLogDto : EntityDto<long>
   {
       public DateTime ExecutionTime { get; set; }
       
       public string Exception { get; set; }
       
       public string BrowserInfo { get; set; }
       
       public string ClientName { get; set; }
       
       public string ClientIpAddress { get; set; }
       
       public int ExecutionDuration { get; set; }
       
       public string ReturnValue { get; set; }
       
       public string MethodName { get; set; }
       
       public string ServiceName { get; set; }
       
       public long? UserId { get; set; }
       
      public string Parameters { get; set; }
      
      public string CustomData { get; set; }
      
      // How fill this field in mapper
      public UserDto User { get; set; }
   }

[demirmusa]

You can check Queryable.Join (System.Linq) as @acjh mentioned. There are similar examples in there.

[demirmusa]

from auditLog in _auditLogRepository.GetAll()
join user in _userRepository.GetAll() on auditLog.UserId equals user.Id into userJoin
from joinedUser in userJoin.DefaultIfEmpty()
where auditLog.UserId == input.UserId 
select new AuditLogAndUser { AuditLog = auditLog, User = joinedUser };