using System.Linq; // 创建LINQ to SQL的数据上下文对象 var dbContext = new YourDataContext(); // 执行LINQ查询,获取计算列的distinct值 var distinctValues = dbContext.YourTable .Select(x => x.ComputedColumn) // 替换为计算列的名称 .Dis
LINQ to SQL语句(2)之Select/Distinct适用场景:o(∩_∩)o… 查询呗。说明:和SQL命令中的select作用相似但位置不同,查询表达式中的select及所接子句是放在表达式最后并把子句中的变量也就是结果返回回来;延迟。Select/Distinct操作包括9种形式,分别为简单用法、匿名类型形式、条件形式、指定类型形式、筛选形式、整形类...
作为一个云计算领域的专家,我了解到LINQ to SQL是一种用于处理SQL数据库的语言集成查询(Language Integrated Query)技术,它允许开发者使用C#或Visual Basic编写查询语句,以便从SQL数据库中检索和操作数据。 在这个问答内容中,我们要使用GROUP BY和COUNT(DISTINCT)语句来查询数据。GROUP BY语句用于将数据分组,以便我们...
linq to sql之Distinct Distict用来排除相同序列中元素的,对于基础类型,可以直接使用Distinct,如: int[] a = {1, 2, 2, 3, 3, 3, 4}; var reslut = a.Distinct(); 结果是1,2,3,4 但对于自定义类型,则需要额外的一些操作,方式有多种,这里选择其中一种,即实现IEquatable<T>,如: usingSystem; usi...
LINQ to SQL 语句(2)之 Select/Distinct [1] Select 介绍 1 [2] Select 介绍 2 [3] Select 介绍 3 和 Distinct 介绍 Select/Distinct 操作符 适用场景:o(∩_∩) o„ 查询呗。 说明:和 SQL 命令中的 select 作用相似但位置不同,查询表达式中的 select 及所接子句是 ...
I'm doing a GroupBy to get the distinct dates but it seems to be ignoring the OrderByDescending (I still get the oldest dates first). Maybe it's the combination of GroupBy, OrderByDescending and Take that is causing the problem although when I remove the Take I still have an issue ...
Do I need to create a new item to set = to the LEFT results and do it that way? EDIT: This is all I want in SQL: SELECT DISTINCTLEFT(LName,1**)** AS FirstLetterOfLast FROM Users ORDER BYLEFT(LName,1 ) All replies (2) ...
For this, LINQ to SQL defines the Column attribute. C# Copy [Table(Name="Customers")] public class Customer { [Column(IsPrimaryKey=true)] public string CustomerID; [Column] public string City; } Visual Basic Copy <Table(Name:="Customers")> _ Public Class Customer <Column(IsPrimary...
Fixed length character types. Transact-SQL distinguishes between Unicode and non-Unicode categories and has three distinct types in each category: fixed length nchar/char, variable length nvarchar/varchar, and larger-sized ntext/text. The fixed length character types could be mapped to the CLRSystem...
Masuit.Tools.NoSQL.MongoDBClient mongodb的封装操作类独立包 为工具库注册配置 工具库需要用到外部配置节,.NET Framework项目配置在web.config/app.config的AppSettings配置节中,.NET Core项目配置在appsettings.json中: EmailDomainWhiteList,邮箱校验需要用到的白名单域名,英文逗号分隔,每个元素支持正则表达式,若未配置...