如何在 linq pad 中执行左联接 -

Question

如何让 linq pad 运行我的左联接，如下所示？

var query = 
            from s in db.CDBLogsHeaders
                    .OrderByDescending(g => g.LogDateTime)
                    from sc in db.StyleColors
                        .Where(stylecolor => stylecolor.id == (int?)s.StyleColorID)
                        .DefaultIfEmpty()
                    from c in db.StyleHeaders
                        .Where(styleHeader => styleHeader.id == (int?)s.StyleHeaderID)
                        .DefaultIfEmpty()
        select new 
        {
            CDBLogsHeaderId = s.Id,
            Merchandiser = c.Merchandiser,
            Material = s.Material,
            Season = s.Season,
            LogsHeaderLogType = s.LogType,
            PushFromTo = s.PushFromTo,
            LinePlan = s.LinePlan,
            QuikRefNumber = s.QuikRefNumber,
            PLMOrigin = s.PLM_Origin,
            SeasonOriginal = c.SeasonOriginal,
            SeasonCurrent = c.SeasonCurrent,
            StyleHeaderId = c.Id,
            StyleCode = c.StyleCode,
            StyleColorsColorCode = sc.ColorCode
        };
    query.Dump();

linq pad 创建的 sql 在 Management Studio 中完美运行，但 linq-pad 不显示任何行并给出此错误

无效操作异常：不能将空值分配给 类型为 System.Int32 的成员，该成员是不可为空的值类型。

如何让 linqpad 工作以便我可以使用它？

Answer 1

在您的匿名类型中，确保您的整数返回 int。

改变

StyleHeaderId = c.Id,

自

StyleHeaderId = (c.Id == null ? 0 : c.Id),