如何在字段中返回空值的记录 [英] How to return the record with null value in a field

问题描述

我想在已奖励字段中返回空值的记录。我尝试编码为

I want to return records with null value in the field 'Awarded'. I tried to code as

public int ReadAllPendingApplicationByBorough(int AcademicYearID, int BoroughID)
        {
            int recordCount = 0;

            recordCount = (from p in currentContext.SignOffs
                           join q in currentContext.Schools on p.SchoolID equals q.SchoolID
                           where q.BoroughID == BoroughID
                           && p.Submitted == true
                           && p.Awarded.ToString()==null
                           && p.AcademicYearID==AcademicYearID
                           select p).Count();
            return recordCount;
        }

但仍然没有返回正确的价值



当我在SQl服务器中查询相同时仍然​​无法正常工作，如果我将获奖的条件更改为获奖为空，则表明工作正常。但我无法给出获奖的条件，就像它显示为错误信息一样。



任何人都可以帮我编码这个

but still it is not returning the correct value

when I queried the same in SQl server still it is not working and if I change condition for Awarded as 'Awarded is null' it is working fine. But I couldn't give the condition for Awarded in the same way as it shows as error message for that.

Can anyone help me to code this

推荐答案

尝试

Try

&& p.Awarded.ToString()==DBNull.Value

而不是。

尝试删除 ToString 调用：

Try removing the ToString call:

&& p.Awarded == null

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