在 ef core 2.2 中执行'select * from (select * from ...)'查询

Question

我正在尝试使用Entity Framework Core 2.2

在c＃中使用该字样（SQL）执行类似的查询（SQL）

select ST_LengthSpheroid(ST_MakeLine(a."Location"),'SPHEROID["WGS 84",6378137,298.257223563]') AS Length
from (select * from "Logs" where "CarId" = 191
      order by "Id") as a;

在Entity Framework> 2.0中，我尝试执行左连接，但是使用自定义功能，我遇到了EF核心警告或错误。是否有适当的方法来实施该查询？

Answer 1

会有类似的工作吗？

select ST_LengthSpheroid(ST_MakeLine(TrackerLogs.Location),'SPHEROID["WGS 84",6378137,298.257223563]') AS Length
from TrackerLogs
where CarId = 191
order by Id

Answer 2

好吧，也许任何人都知道一个更好的解决方案，但是经过一些研究，我无法使用 pure ef core实现这一目标，所以我已经使用了FromSql

var queryable = qLogs.FromSql("select * from "" + tableName + "" order by "" + orderField + """);
var result = qCars.Select(x => new RouteModel
{
   Mileage = Math.Round(
       queryable
           .Where(y => y.CarId == x.Id)
           .Select(y => PostgisExtensions.ST_LengthSpheroid(
                    PostgisExtensions.ST_MakeLine(
                        PostgisExtensions.ST_GeomFromText(y.Location.AsText(),          PostgisConstants.MetricSrid)
                    ),
                   PostgisConstants.SpheroidWgs84)
           )
           .FirstOrDefault() / 1000),
 .....

因此，现在我可以使用groupby或CC_3或distinct on使用子选择。完美工作，没有任何EF核心警告并生成预期查询：

  SELECT ROUND(COALESCE((
      SELECT ST_LengthSpheroid(ST_MakeLine(ST_GeomFromText(ST_AsText(x0."Location"), 4326)), 'SPHEROID["WGS 84",6378137,298.257223563]')
      FROM (
          select * from "Logs" order by "FixedAt"
      ) AS x0
      WHERE (x0."CarId" = x."Id")
      LIMIT 1
  ), 0.0) / 1000.0) AS "Mileage", 
  .....