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 varquery=fromiteminitemswhereitem.Category=="Electronics"whereitem.Price<100selectitem; ...
query = query.Where(p => p.Description.Contains(temp)); } 与 IQueryable<Product> query = ...
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。 var numbers = new List<int> { 1, 2, 3, 4, 5 ...
"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 ...
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"); ...
Self-joinDouble and multiple joinsJoin using entity fieldsLate-binding left joinUse the Equals operatorUse the Not Equals operatorUse a method-based LINQ query with a Where clauseUse the Greater Than operatorUse the Greater Than or Equals and Less Than or Equals operators...
(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 ...
(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...
Where操作 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: 1.简单形式: 例如:使
The reason for this is optimization I would like to implement in my application, where data filtering would be performed using subquery if only one SQL query would be produced. In case of generating multiple SQL queries, I would first execute query that filters data (and return only Ids of ...