在LINQ(Language Integrated Query)中,多个WHERE子句可以用来对查询结果进行多个条件的筛选。在C#和Visual Basic中,可以使用链式方法调用来实现多个WHERE子句。 以下是一个使用多个WHERE子句的LINQ查询示例: 代码语言:csharp 复制 var query = from item in items where item.Category
下面我们来学习LinQ常用操作符一、筛选操作符Where 根据谓词对源序列的内容进行筛选,类似于SQL中的where子句。...cust; 二、投影运算符投影运算符对应SQL中的“select 列名”子句(一)Select Select操作符是从序列源返回一组指定属性使用扩展方法 var infos = context.Infos.Where...,从序列第一个元素开始依次判断,...
IQueryable<User> query = context.Users; foreach (string keyword in keywords) { string temp = keyword; query = query.Where(u => u.Name.Contains(temp) || u.State.Contains(temp) || u.HashTags.Contains(temp)); } query.Include("WhoHasBlockedMe").Include("Friends"); var users = que...
"2000.10") table.Rows.Add(2, "Tom", "3000.00") Dim query = table.AsEnumerable().Where(Function(x) x.Field(Of String)("Name") = "Scott" AndAlso x.Field(Of Integer)("Id") = 1).Sum(Function(x) Convert.ToDecimal(x.Field(Of String)("Salary"))) Dim total As Decimal = query ...
LINQ to SQL语句(1)之Where适用场景:实现过滤,查询等功能。说明:与SQL命令中的Where作用相似,都是起到范围限定也就是过滤作用的,而判断条件就是它后面所接的子句。Where操作包括3种形式,分别为简单形式、关系条件形式、First()形式。下面分别用实例举例下:...
usr/local/share/dotnet/sdk"; var fileList = Directory.GetFiles(startFolder, "*.*", SearchOption.AllDirectories); var fileQuery = from file in fileList let fileLen = new FileInfo(file).Length where fileLen > 0 select fileLen; // Cache the results to avoid multiple trips to the ...
(file).LengthwherefileLen >0selectfileLen;// Cache the results to avoid multiple trips to the file system.long[] fileLengths = fileQuery.ToArray();// Return the size of the largest filelonglargestFile = fileLengths.Max();// Return the total number of bytes in all the files...
在LINQ(Language Integrated Query)中,提供了许多方法用于查询和操作数据。这些方法可用于对各种数据源(如集合、数组、数据库表等)执行查询、筛选、排序、投影、分组、聚合等操作。以下是一些常见的 LINQ 方法: 筛选方法 Where Where: 根据指定条件筛选元素。
Northwnd db =newNorthwnd(@"c:\northwnd.mdf");// Query for customers in London.IQueryable<Customer> custQuery =fromcustindb.Customerswherecust.City =="London"selectcust; For more information about how to create specific types of data sources, see the documentation for the various LINQ providers...
To further refine the query, you can combine multiple Boolean conditions in thewhereclause. The following code adds a condition so that the query returns those students whose first score was over 90 and whose last score was less than 80. Thewhereclause should resemble the following code. ...