使用多个 IEnumerable 连接

Question

如果我有3张桌子。我如何使用 IEnumerable LINQ 连接将所有 3 个表连接在一起？这是我当前的查询，我想使用 GPRow id = Budgettargets id

加入另一个名为 BudgetTargets 的 IEnumerable

var rows = _context.GpRows.Join(
            _context.ShopInfos,
            GpRow => GpRow.ShopId,
            ShopInfo => ShopInfo.ShopId,
            (GpRow, ShopInfo) => new{ 
                ShopName = ShopInfo.ShopName,
                State = ShopInfo.State,
                YearMonth = String.Concat(GpRow.Year, GpRow.Month),
                GpRow.Year,
                GpRow.Month,
                GpRow.Id,
                GpRow.ShopId,
                GpRow.PaintSale,
                GpRow.PanelSale,
                GpRow.PartsSale,
                GpRow.OtherSale,
                GpRow.PaintCost,
                GpRow.PanelCost,
                GpRow.PartsCost,
                GpRow.OtherCost,
                GpRow.PanelWages,
                GpRow.PaintWages,
                GpRow.Depreciation,
                GpRow.ForecastedSales,
                GpRow.Expenses
            }
        )
        .Where(GpRow => shopId_Array.Contains(GpRow.ShopId))
        .OrderByDescending(a => a.Year).OrderByDescending(b => b.Month).ThenBy(c => c.State).ThenBy(c => c.ShopName)
        .ToList();

Answer 1

我同意@juharr 的评论。 LINQ 查询格式有时比流畅的 API 风格的意图更清晰。以下是查询的编写方式。

var rows = from GpRow in _context.GpRows
    join ShopInfo in _context.ShopInfos on GpRow.ShopId equals ShopInfo.ShopId
    orderby GpRow.ShopId descending, GpRow.Month descending, ShopInfo.State, ShopInfo.ShopName
    select new { 
        ShopName = ShopInfo.ShopName,
        State = ShopInfo.State,
        YearMonth = String.Concat(GpRow.Year, GpRow.Month),
        GpRow.Year,
        GpRow.Month,
        GpRow.Id,
        GpRow.ShopId,
        GpRow.PaintSale,
        GpRow.PanelSale,
        GpRow.PartsSale,
        GpRow.OtherSale,
        GpRow.PaintCost,
        GpRow.PanelCost,
        GpRow.PartsCost,
        GpRow.OtherCost,
        GpRow.PanelWages,
        GpRow.PaintWages,
        GpRow.Depreciation,
        GpRow.ForecastedSales,
        GpRow.Expenses
    };

使用多个 IEnumerable 连接

using multiple IEnumerable Joins

c#

linq

ienumerable