Question

如何获得linq pad来运行我的左连接，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中运行完美，但linq-pad不显示任何行并给出此错误

InvalidOperationException：无法将null值分配给a System.Int32类型的成员，它是一个不可为空的值类型。

如何让linqpad工作，以便我可以玩它？

Answer 1

在您的匿名类型中，请确保您的整数正在返回整数。

更改

StyleHeaderId = c.Id,

要

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

如何在linqpad中执行左连接 -

1 个答案: