如何在c＃中使用多数据搜索来搜索记录 [英] How to search record using multidata search in c#

问题描述

如何使用多数据搜索搜索记录



我有三个数据来搜索记录

类

部分

流



例如

How to search record using multidata search

I have three data to search a record
Class
Section
Stream

For Exampale

"Select * from tb_StudentInfo where Class="Value" and Section="Value" and Stream="Value"";
this query return correct value

但如果One值缺失

But if One value missing

"Select * from tb_StudentInfo where Class="Value" and Section="null" and Stream="null"";

查询什么都不返回



如何解决这个问题???

query return nothing

How to solve this problem???

推荐答案

put与一起查询和检查空列

put the query like and check null column with is null

"Select * from tb_StudentInfo where Class="Value" and Section is null  and Stream is null ";  

先生，尝试让你的查询有点动态



例如。访问尝试此代码

sir, try making your query a little dynamic

For eg. for access try this code

"Select * from tb_StudentInfo 
where Class=' & Value & '
 iif(IsNull('Your value')=false,' and Section=' & value,'') & 
 and iif(IsNull('Your value')=false,' and Stream=' & value,'')";

在上面的示例中它将搜索值是否为空查询变为此

in the above example it will search if the value is null the query becomes this

"Select * from tb_StudentInfo where Class="Value"";

对于您的要求，您可能需要构建动态查询

For ur requirement you may need to build dynamic query

string query="Select * from tb_StudentInfo ";

if(Class!=null&&Section!=null&&Stream!=null)
{
query=query+"where Class="Value" and Section="Value" and Stream="Value"";
}
else if(Section==null&&Stream==null)
{
query=query+"where  Class="Value"";
}
else if(Class==null&&Stream==null)
{
query=query+"where Section="Value"";
}
else if(Class==null&&Section==null)
{
query=query+"where Stream="Value"";
}
else if(Class==null)
{
query=query+"where Section="Value" and Stream="Value"";
}
else if(Section==null)
{
query=query+"where Class="Value" and Stream="Value"";
}
else if(Stream==null)
{
query=query+"where Section="Value" and Class="Value"";
}

Now you can use query variable

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