在 Linq 中使用布尔数据类型检查 where 子句中的两个条件时列表为空

Question

在 linq 中，我遇到了一个奇怪的问题。每当我尝试在 where 子句中使用 bit datatype 指定两列时，它都会返回 null。但问题是在我的 table.

中存在具有该特定要求的数据

var data = (from PD in C.KYC_PERSONAL_DETAILS
                 join IMG in C.KYC_UPLOAD_DETAILS on PD.ACCOOUNT_NO equals IMG.ACCOOUNT_NO
                 where ( PD.FILEFLAG == false) && (IMG.IsVerify == true )
                 select new
                 {
                 PD_ACCOUNT_NO = PD.ACCOOUNT_NO,
                 PD_NAME = PD.NAME,
                 IMG_Name = IMG.Name
                 }.ToList();
      int count = data.Count(); //Here it shows 0 even though data exists in table.

相同的查询，如果我以 SQL 查询的形式编写，然后工作并返回一行。

select * from KYC_PERSONAL_DETAILS, KYC_UPLOAD_DETAILS 
        where KYC_PERSONAL_DETAILS.FILEFLAG = false 
        AND KYC_UPLOAD_DETAILS.IS_VERIFY= true

//Here it is returning a row.

我只想知道是否可以在 linq 的 where 子句中使用布尔数据类型和 && 运算符指定两列？如果是，那么请提出一个方法。

Answer 1

经过反复试验后，我找到了使 LINQ 查询正常工作的方法。虽然我仍然不知道背后的原因，但如果我通过以下任何一种方式进行操作，它现在就可以工作了。在研究了这背后的实际问题和逻辑之后，我会更新我的答案。

如果我编写与

相同的查询

1.

var data = (from PD in C.KYC_PERSONAL_DETAILS
             join IMG in C.KYC_UPLOAD_DETAILS on PD.ACCOOUNT_NO equals IMG.ACCOOUNT_NO
             where PD.FILEFLAG == false
             where IMG.IsVerify == true 
             select new
             {
             PD_ACCOUNT_NO = PD.ACCOOUNT_NO,
             PD_NAME = PD.NAME,
             IMG_Name = IMG.Name
             }.ToList();
  int count = data.Count(); //Here it shows 1 data that exists in table.

2.

var data = (from PD in C.KYC_PERSONAL_DETAILS
             join IMG in C.KYC_UPLOAD_DETAILS on PD.ACCOOUNT_NO equals IMG.ACCOOUNT_NO
             where ( PD.FILEFLAG == false) & (IMG.IsVerify == true )
             select new
             {
             PD_ACCOUNT_NO = PD.ACCOOUNT_NO,
             PD_NAME = PD.NAME,
             IMG_Name = IMG.Name
             }.ToList();
  int count = data.Count(); //Here it shows 1 data that exists in table.

通过在布尔数据类型的情况下编写相同的查询，它运行良好。我认为使用短路运算符可能会有问题。

So, At the end either using & instead of && or using two where in LINQ query will work well whenever you want to deal with two columns with boolean datatype. Using && for other datatypes is alright but in case of boolean it could create problems.

更新 1

作为旁注

Though using 2nd Option is not recommended as stated by Ivan in comments. Because I'm using SQL SERVER 2008 R2 and Ivan claims that using && in non sql DB is working fine and it's also possible that I might be facing a bug in SQL Server..

在 Linq 中使用布尔数据类型检查 where 子句中的两个条件时列表为空

List is null when checking for two conditions in where clause with boolean datatype in Linq

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