原来的代码是
if (string.IsNullOrWhiteSpace(seal)) seal = null;
ctx.Terminal.FirstOrDefault(ent=>ent.Seal==seal)
当seal是null时成长的sql语句如下，采用=null执行结果不是需要的
exec sp_executesql N'SELECT TOP (1)
[Extent1].[id] AS [id],
[Extent1].[Terminal] AS [Terminal],
[Extent1].[Die] AS [Die],
[Extent1].[WireGauge] AS [WireGauge],
[Extent1].[NormCCH] AS [NormCCH],
[Extent1].[ActualCCH] AS [ActualCCH],
[Extent1].[NormCCW] AS [NormCCW],
[Extent1].[ActualCCW] AS [ActualCCW],
[Extent1].[NormICH] AS [NormICH],
[Extent1].[ActualICH] AS [ActualICH],
[Extent1].[NormICW] AS [NormICW],
[Extent1].[ActualICW] AS [ActualICW],
[Extent1].[NormPullForce] AS [NormPullForce],
[Extent1].[UpPullForce] AS [UpPullForce],
[Extent1].[DownPullForce] AS [DownPullForce],
[Extent1].[ActualPullForce] AS [ActualPullForce],
[Extent1].[WireType] AS [WireType],
[Extent1].[Seal] AS [Seal],
[Extent1].[Supplier] AS [Supplier],
[Extent1].[Project] AS [Project],
[Extent1].[StripLength] AS [StripLength],
[Extent1].[coreup] AS [coreup],
[Extent1].[coredown] AS [coredown],
[Extent1].[platicup] AS [platicup],
[Extent1].[platicdown] AS [platicdown],
[Extent1].[sample] AS [sample],
[Extent1].[Tester] AS [Tester],
[Extent1].[picture] AS [picture],
[Extent1].[testdate] AS [testdate],
[Extent1].[date] AS [date],
[Extent1].[yj] AS [yj],
[Extent1].[standardY1] AS [standardY1],
[Extent1].[standardY2] AS [standardY2],
[Extent1].[standardY3] AS [standardY3],
[Extent1].[standardY4] AS [standardY4],
[Extent1].[standardY5] AS [standardY5],
[Extent1].[standardY6] AS [standardY6],
[Extent1].[standardY7] AS [standardY7],
[Extent1].[standardY8] AS [standardY8],
[Extent1].[standardY9] AS [standardY9],
[Extent1].[standardY10] AS [standardY10],
[Extent1].[standardN1] AS [standardN1],
[Extent1].[standardN2] AS [standardN2],
[Extent1].[standardN3] AS [standardN3],
[Extent1].[standardN4] AS [standardN4],
[Extent1].[standardN5] AS [standardN5],
[Extent1].[standardN6] AS [standardN6],
[Extent1].[standardN7] AS [standardN7],
[Extent1].[standardN8] AS [standardN8],
[Extent1].[standardN9] AS [standardN9],
[Extent1].[standardN10] AS [standardN10],
[Extent1].[plug] AS [plug],
[Extent1].[socket] AS [socket],
[Extent1].[remark1] AS [remark1],
[Extent1].[remark] AS [remark],
[Extent1].[CCHUp] AS [CCHUp],
[Extent1].[CCWUp] AS [CCWUp],
[Extent1].[ICHUp] AS [ICHUp],
[Extent1].[ICWUp] AS [ICWUp],
[Extent1].[CCHDown] AS [CCHDown],
[Extent1].[CCWDown] AS [CCWDown],
[Extent1].[ICHDown] AS [ICHDown],
[Extent1].[ICWDown] AS [ICWDown],
[Extent1].[CCH] AS [CCH],
[Extent1].[CCW] AS [CCW],
[Extent1].[ICH] AS [ICH],
[Extent1].[ICW] AS [ICW]
FROM (SELECT
[Terminal].[id] AS [id],
[Terminal].[Terminal] AS [Terminal],
[Terminal].[Die] AS [Die],
[Terminal].[WireGauge] AS [WireGauge],
[Terminal].[NormCCH] AS [NormCCH],
[Terminal].[ActualCCH] AS [ActualCCH],
[Terminal].[NormCCW] AS [NormCCW],
[Terminal].[ActualCCW] AS [ActualCCW],
[Terminal].[NormICH] AS [NormICH],
[Terminal].[ActualICH] AS [ActualICH],
[Terminal].[NormICW] AS [NormICW],
[Terminal].[ActualICW] AS [ActualICW],
[Terminal].[NormPullForce] AS [NormPullForce],
[Terminal].[UpPullForce] AS [UpPullForce],
[Terminal].[DownPullForce] AS [DownPullForce],
[Terminal].[ActualPullForce] AS [ActualPullForce],
[Terminal].[WireType] AS [WireType],
[Terminal].[Seal] AS [Seal],
[Terminal].[Supplier] AS [Supplier],
[Terminal].[Project] AS [Project],
[Terminal].[StripLength] AS [StripLength],
[Terminal].[coreup] AS [coreup],
[Terminal].[coredown] AS [coredown],
[Terminal].[platicup] AS [platicup],
[Terminal].[platicdown] AS [platicdown],
[Terminal].[sample] AS [sample],
[Terminal].[Tester] AS [Tester],
[Terminal].[picture] AS [picture],
[Terminal].[testdate] AS [testdate],
[Terminal].[date] AS [date],
[Terminal].[yj] AS [yj],
[Terminal].[standardY1] AS [standardY1],
[Terminal].[standardY2] AS [standardY2],
[Terminal].[standardY3] AS [standardY3],
[Terminal].[standardY4] AS [standardY4],
[Terminal].[standardY5] AS [standardY5],
[Terminal].[standardY6] AS [standardY6],
[Terminal].[standardY7] AS [standardY7],
[Terminal].[standardY8] AS [standardY8],
[Terminal].[standardY9] AS [standardY9],
[Terminal].[standardY10] AS [standardY10],
[Terminal].[standardN1] AS [standardN1],
[Terminal].[standardN2] AS [standardN2],
[Terminal].[standardN3] AS [standardN3],
[Terminal].[standardN4] AS [standardN4],
[Terminal].[standardN5] AS [standardN5],
[Terminal].[standardN6] AS [standardN6],
[Terminal].[standardN7] AS [standardN7],
[Terminal].[standardN8] AS [standardN8],
[Terminal].[standardN9] AS [standardN9],
[Terminal].[standardN10] AS [standardN10],
[Terminal].[plug] AS [plug],
[Terminal].[socket] AS [socket],
[Terminal].[remark1] AS [remark1],
[Terminal].[remark] AS [remark],
[Terminal].[CCHUp] AS [CCHUp],
[Terminal].[CCWUp] AS [CCWUp],
[Terminal].[ICHUp] AS [ICHUp],
[Terminal].[ICWUp] AS [ICWUp],
[Terminal].[CCHDown] AS [CCHDown],
[Terminal].[CCWDown] AS [CCWDown],
[Terminal].[ICHDown] AS [ICHDown],
[Terminal].[ICWDown] AS [ICWDown],
[Terminal].[CCH] AS [CCH],
[Terminal].[CCW] AS [CCW],
[Terminal].[ICH] AS [ICH],
[Terminal].[ICW] AS [ICW]
FROM [dbo].[Terminal] AS [Terminal]) AS [Extent1]
WHERE ([Extent1].[Terminal] = @p__linq__0) AND ([Extent1].[WireGauge] = @p__linq__1) AND ([Extent1].[Die] LIKE N''Q%'') AND ([Extent1].[WireType] = @p__linq__2) AND ([Extent1].[Seal] = @p__linq__3)',N'@p__linq__0 nvarchar(4000),@p__linq__1 nvarchar(4000),@p__linq__2 nvarchar(4000),@p__linq__3 nvarchar(4000)',@p__linq__0=N'968221-1',@p__linq__1=N'0.50',@p__linq__2=N'GHB2',@p__linq__3=N'NULL'
换成下面代码后生成的语句变成了Is null 正确匹配了结果
exec sp_executesql N'SELECT TOP (1)
[Extent1].[id] AS [id],
[Extent1].[Terminal] AS [Terminal],
[Extent1].[Die] AS [Die],
[Extent1].[WireGauge] AS [WireGauge],
[Extent1].[NormCCH] AS [NormCCH],
[Extent1].[ActualCCH] AS [ActualCCH],
[Extent1].[NormCCW] AS [NormCCW],
[Extent1].[ActualCCW] AS [ActualCCW],
[Extent1].[NormICH] AS [NormICH],
[Extent1].[ActualICH] AS [ActualICH],
[Extent1].[NormICW] AS [NormICW],
[Extent1].[ActualICW] AS [ActualICW],
[Extent1].[NormPullForce] AS [NormPullForce],
[Extent1].[UpPullForce] AS [UpPullForce],
[Extent1].[DownPullForce] AS [DownPullForce],
[Extent1].[ActualPullForce] AS [ActualPullForce],
[Extent1].[WireType] AS [WireType],
[Extent1].[Seal] AS [Seal],
[Extent1].[Supplier] AS [Supplier],
[Extent1].[Project] AS [Project],
[Extent1].[StripLength] AS [StripLength],
[Extent1].[coreup] AS [coreup],
[Extent1].[coredown] AS [coredown],
[Extent1].[platicup] AS [platicup],
[Extent1].[platicdown] AS [platicdown],
[Extent1].[sample] AS [sample],
[Extent1].[Tester] AS [Tester],
[Extent1].[picture] AS [picture],
[Extent1].[testdate] AS [testdate],
[Extent1].[date] AS [date],
[Extent1].[yj] AS [yj],
[Extent1].[standardY1] AS [standardY1],
[Extent1].[standardY2] AS [standardY2],
[Extent1].[standardY3] AS [standardY3],
[Extent1].[standardY4] AS [standardY4],
[Extent1].[standardY5] AS [standardY5],
[Extent1].[standardY6] AS [standardY6],
[Extent1].[standardY7] AS [standardY7],
[Extent1].[standardY8] AS [standardY8],
[Extent1].[standardY9] AS [standardY9],
[Extent1].[standardY10] AS [standardY10],
[Extent1].[standardN1] AS [standardN1],
[Extent1].[standardN2] AS [standardN2],
[Extent1].[standardN3] AS [standardN3],
[Extent1].[standardN4] AS [standardN4],
[Extent1].[standardN5] AS [standardN5],
[Extent1].[standardN6] AS [standardN6],
[Extent1].[standardN7] AS [standardN7],
[Extent1].[standardN8] AS [standardN8],
[Extent1].[standardN9] AS [standardN9],
[Extent1].[standardN10] AS [standardN10],
[Extent1].[plug] AS [plug],
[Extent1].[socket] AS [socket],
[Extent1].[remark1] AS [remark1],
[Extent1].[remark] AS [remark],
[Extent1].[CCHUp] AS [CCHUp],
[Extent1].[CCWUp] AS [CCWUp],
[Extent1].[ICHUp] AS [ICHUp],
[Extent1].[ICWUp] AS [ICWUp],
[Extent1].[CCHDown] AS [CCHDown],
[Extent1].[CCWDown] AS [CCWDown],
[Extent1].[ICHDown] AS [ICHDown],
[Extent1].[ICWDown] AS [ICWDown],
[Extent1].[CCH] AS [CCH],
[Extent1].[CCW] AS [CCW],
[Extent1].[ICH] AS [ICH],
[Extent1].[ICW] AS [ICW]
FROM (SELECT
[Terminal].[id] AS [id],
[Terminal].[Terminal] AS [Terminal],
[Terminal].[Die] AS [Die],
[Terminal].[WireGauge] AS [WireGauge],
[Terminal].[NormCCH] AS [NormCCH],
[Terminal].[ActualCCH] AS [ActualCCH],
[Terminal].[NormCCW] AS [NormCCW],
[Terminal].[ActualCCW] AS [ActualCCW],
[Terminal].[NormICH] AS [NormICH],
[Terminal].[ActualICH] AS [ActualICH],
[Terminal].[NormICW] AS [NormICW],
[Terminal].[ActualICW] AS [ActualICW],
[Terminal].[NormPullForce] AS [NormPullForce],
[Terminal].[UpPullForce] AS [UpPullForce],
[Terminal].[DownPullForce] AS [DownPullForce],
[Terminal].[ActualPullForce] AS [ActualPullForce],
[Terminal].[WireType] AS [WireType],
[Terminal].[Seal] AS [Seal],
[Terminal].[Supplier] AS [Supplier],
[Terminal].[Project] AS [Project],
[Terminal].[StripLength] AS [StripLength],
[Terminal].[coreup] AS [coreup],
[Terminal].[coredown] AS [coredown],
[Terminal].[platicup] AS [platicup],
[Terminal].[platicdown] AS [platicdown],
[Terminal].[sample] AS [sample],
[Terminal].[Tester] AS [Tester],
[Terminal].[picture] AS [picture],
[Terminal].[testdate] AS [testdate],
[Terminal].[date] AS [date],
[Terminal].[yj] AS [yj],
[Terminal].[standardY1] AS [standardY1],
[Terminal].[standardY2] AS [standardY2],
[Terminal].[standardY3] AS [standardY3],
[Terminal].[standardY4] AS [standardY4],
[Terminal].[standardY5] AS [standardY5],
[Terminal].[standardY6] AS [standardY6],
[Terminal].[standardY7] AS [standardY7],
[Terminal].[standardY8] AS [standardY8],
[Terminal].[standardY9] AS [standardY9],
[Terminal].[standardY10] AS [standardY10],
[Terminal].[standardN1] AS [standardN1],
[Terminal].[standardN2] AS [standardN2],
[Terminal].[standardN3] AS [standardN3],
[Terminal].[standardN4] AS [standardN4],
[Terminal].[standardN5] AS [standardN5],
[Terminal].[standardN6] AS [standardN6],
[Terminal].[standardN7] AS [standardN7],
[Terminal].[standardN8] AS [standardN8],
[Terminal].[standardN9] AS [standardN9],
[Terminal].[standardN10] AS [standardN10],
[Terminal].[plug] AS [plug],
[Terminal].[socket] AS [socket],
[Terminal].[remark1] AS [remark1],
[Terminal].[remark] AS [remark],
[Terminal].[CCHUp] AS [CCHUp],
[Terminal].[CCWUp] AS [CCWUp],
[Terminal].[ICHUp] AS [ICHUp],
[Terminal].[ICWUp] AS [ICWUp],
[Terminal].[CCHDown] AS [CCHDown],
[Terminal].[CCWDown] AS [CCWDown],
[Terminal].[ICHDown] AS [ICHDown],
[Terminal].[ICWDown] AS [ICWDown],
[Terminal].[CCH] AS [CCH],
[Terminal].[CCW] AS [CCW],
[Terminal].[ICH] AS [ICH],
[Terminal].[ICW] AS [ICW]
FROM [dbo].[Terminal] AS [Terminal]) AS [Extent1]
WHERE ([Extent1].[Terminal] = @p__linq__0) AND ([Extent1].[WireGauge] = @p__linq__1) AND ([Extent1].[WireType] = @p__linq__2) AND ([Extent1].[Die] LIKE N''Q%'') AND ([Extent1].[Seal] IS NULL)',N'@p__linq__0 nvarchar(4000),@p__linq__1 nvarchar(4000),@p__linq__2 nvarchar(4000)',@p__linq__0=N'968221-1',@p__linq__1=N'0.50',@p__linq__2=N'GHB2'
C#代码 需要调用时显式的使用 ctx.Terminal.where(net=>ent.Seal==null) ,才能生成 is null的SQL语句
using (var mfgCtx = com.geelyhd.MFG.EFModel.DBCtx.GetCtx())
{
var q = mfgCtx.Terminal.Where(ent => ent.Terminal1 == ter && ent.WireGauge == card.Guage && ent.WireType == card.Wire_kinds);
if (terArr[i].CCHType == "30高度")
{ q = q.Where(ent=> !ent.Die.StartsWith("Q") ); }
else //40高度带Q
{ q = q.Where(ent => ent.Die.StartsWith("Q")); }
if (seal == null)
{
q = q.Where(ent => ent.Seal == null);
}
else
{
q = q.Where(ent => ent.Seal == seal);
}
it = q.FirstOrDefault(); }