SQL-LINQ-Lambda语法对照，好记性不如烂笔头

忘记的时候就翻阅翻阅吧~~

SQL

LINQ

Lambda

SELECT *FROM HumanResources.Employee

from e in Employees

select e

Employees .Select (e => e)

SELECT e.LoginID, e.JobTitle

FROM HumanResources.Employee AS e

from e in Employees

select new {e.LoginID, e.JobTitle}

Employees.Select (
      e => new {
            LoginID = e.LoginID,
            JobTitle = e.JobTitle
         }
   )

SELECT e.LoginID AS ID, e.JobTitle AS Title

FROM HumanResources.Employee AS e

from e in Employees

select new {ID = e.LoginID, Title = e.JobTitle}

Employees.Select (
      e => new
         {
            ID = e.LoginID,
            Title = e.JobTitle
         }
   )

SELECT DISTINCT e.JobTitle

FROM HumanResources.Employee AS e

(from e in Employees

select e.JobTitle).Distinct()

Employees
.Select (e => e.JobTitle)
.Distinct ()

SELECT e.*

FROM HumanResources.Employee AS e

WHERE e.LoginID = 'test'

from e in Employees

where e.LoginID == "test"

select e

Employees
.Where (e => (e.LoginID == "test"))

SELECT e.*

FROM HumanResources.Employee AS e

WHERE e.LoginID = 'test' AND e.SalariedFlag = 1

from e in Employees

where e.LoginID == "test" && e.SalariedFlag

select e

Employees
.Where (e => ((e.LoginID == "test") && e.SalariedFlag))

SELECT e.* FROM HumanResources.Employee AS e

WHERE e.VacationHours >= 2 AND e.VacationHours <= 10

from e in Employees

where e.VacationHours >= 2 && e.VacationHours <= 10

select e

Employees
.Where (e => (((Int32)(e.VacationHours) >= 2) && ((Int32)(e.VacationHours) <= 10)))

SELECT e.* FROM HumanResources.Employee AS e
ORDER BY e.NationalIDNumber

from e in Employees

orderby e.NationalIDNumber

select e

Employees
.OrderBy (e => e.NationalIDNumber)

SELECT e.* FROM HumanResources.Employee AS e

ORDER BY e.HireDate DESC, e.NationalIDNumber

from e in Employees

orderby e.HireDate descending, e.NationalIDNumber

select e

Employees
.OrderByDescending (e => e.HireDate)
.ThenBy (e => e.NationalIDNumber)

SELECT e.* FROM HumanResources.Employee AS e

WHERE e.JobTitle LIKE 'Vice%' OR SUBSTRING(e.JobTitle, 0, 3) = 'Pro'

from e in Employees

where e.JobTitle.StartsWith("Vice") || e.JobTitle.Substring(0, 3) == "Pro"

select e

Employees
.Where (e => (e.JobTitle.StartsWith ("Vice") || (e.JobTitle.Substring (0, 3) == "Pro")))

SELECT SUM(e.VacationHours)

FROM HumanResources.Employee AS e

Employees.Sum(e => e.VacationHours);

SELECT COUNT(*) FROM HumanResources.Employee AS e

Employees.Count();

SELECT SUM(e.VacationHours) AS TotalVacations, e.JobTitle

FROM HumanResources.Employee AS e

GROUP BY e.JobTitle

from e in Employees

group e by e.JobTitle into g

select new {JobTitle = g.Key, TotalVacations = g.Sum(e => e.VacationHours)}

Employees
   .GroupBy (e => e.JobTitle)
   .Select (
      g => new
         {
            JobTitle = g.Key,
            TotalVacations = g.Sum (e => (Int32)(e.VacationHours))
         }
   )

SELECT e.JobTitle, SUM(e.VacationHours) AS TotalVacations

FROM HumanResources.Employee AS e

GROUP BY e.JobTitle

HAVING e.COUNT(*) > 2

from e in Employees

group e by e.JobTitle into g

where g.Count() > 2

select new {JobTitle = g.Key, TotalVacations = g.Sum(e => e.VacationHours)}

Employees
   .GroupBy (e => e.JobTitle)
   .Where (g => (g.Count () > 2))
   .Select (
      g =>
         new
         {
            JobTitle = g.Key,
            TotalVacations = g.Sum (e => (Int32)(e.VacationHours))
         }
   )

SELECT *

FROM Production.Product AS p, Production.ProductReview AS pr

from p in Products

from pr in ProductReviews

select new {p, pr}

Products
   .SelectMany (
      p => ProductReviews,
      (p, pr) =>
         new
         {
            p = p,
            pr = pr
         }
   )

SELECT *

FROM Production.Product AS p

INNER JOIN Production.ProductReview AS pr ON p.ProductID = pr.ProductID

from p in Products

join pr in ProductReviews on p.ProductID equals pr.ProductID

select new {p, pr}

Products
   .Join (
      ProductReviews,
      p => p.ProductID,
      pr => pr.ProductID,
      (p, pr) =>
         new
         {
            p = p,
            pr = pr
         }
   )

SELECT *

FROM Production.Product AS p

INNER JOIN Production.ProductCostHistory AS pch ON p.ProductID = pch.ProductID AND p.SellStartDate = pch.StartDate

from p in Products

join pch in ProductCostHistories on new {p.ProductID, StartDate = p.SellStartDate} equals new {pch.ProductID, StartDate = pch.StartDate}

select new {p, pch}

Products
   .Join (
      ProductCostHistories,
      p =>
         new
         {
            ProductID = p.ProductID,
            StartDate = p.SellStartDate
         },
      pch =>
         new
         {
            ProductID = pch.ProductID,
            StartDate = pch.StartDate
         },
      (p, pch) =>
         new
         {
            p = p,
            pch = pch
         }
   )

SELECT *

FROM Production.Product AS p

LEFT OUTER JOIN Production.ProductReview AS pr ON p.ProductID = pr.ProductID

from p in Products

join pr in ProductReviews on p.ProductID equals pr.ProductID

into prodrev

select new {p, prodrev}

Products
   .GroupJoin (
      ProductReviews,
      p => p.ProductID,
      pr => pr.ProductID,
      (p, prodrev) =>
         new
         {
            p = p,
            prodrev = prodrev
         }
   )

SELECT p.ProductID AS ID

FROM Production.Product AS p

UNION

SELECT pr.ProductReviewID

FROM Production.ProductReview AS pr

(from p in Products

select new {ID = p.ProductID}).Union(

from pr in ProductReviews

select new {ID = pr.ProductReviewID})

Products
   .Select (
      p =>
         new
         {
            ID = p.ProductID
         }
   )
   .Union (
      ProductReviews
         .Select (
            pr =>
               new
               {
                  ID = pr.ProductReviewID
               }
         )
   )

SELECT TOP (10) *

FROM Production.Product AS p

WHERE p.StandardCost < 100

(from p in Products

where p.StandardCost < 100

select p).Take(10)

Products
.Where (p => (p.StandardCost < 100))
.Take (10)

SELECT *

FROM [Production].[Product] AS p

WHERE p.ProductID IN(

SELECT pr.ProductID

FROM [Production].[ProductReview] AS [pr]

WHERE pr.[Rating] = 5

)

from p in Products

where (from pr in ProductReviews

where pr.Rating == 5

select pr.ProductID).Contains(p.ProductID)

select p

Products
   .Where (
      p =>
         ProductReviews
            .Where (pr => (pr.Rating == 5))
            .Select (pr => pr.ProductID)
            .Contains (p.ProductID)
   )

直接上实例，学习起来是不是更方便些！

SQL-LINQ-Lambda语法对照，好记性不如烂笔头的更多相关文章

SQL,LINQ,Lambda语法对照图（转载）
如果你熟悉SQL语句,当使用LINQ时,会有似曾相识的感觉.但又略有不同.下面是SQL和LINQ,Lambda语法对照图 SQL LINQ Lambda SELECT * FROM HumanReso ...
好记性不如烂笔头-linux学习笔记1
好记性不如烂笔头-linux学习笔记1 linux的文件系统有ext2,ext3,ext4,目前主流是ext4 linux主要用于服务器级别的操作系统,安装时需要至少2个分区一个是交换分区,swap ...
好记性不如烂笔头-Mysql查找如何判断字段是否包含某个字符串
好记性不如烂笔头-Mysql查找如何判断字段是否包含某个字符串利用mysql 字符串函数 find_in_set(); SELECT * FROM users WHERE find_in_set(' ...
[nodejs]修改全局包位置，修复npm安装全局模块命令失效。好记性不如烂笔头
修复npm -g 全局安装命令失效,好的吧不得不承认,好记性不如烂笔头,我居然会忘记方法哈哈哈 Linux安装nodejs sudo apt install node sudo apt install ...
Common lang一些边界方法总结（好记性不如烂笔头，需要慢慢积累）.一定要利用好现有的轮子，例如Apache common与Google Guava
好记性真是不如烂笔头啊!!!! 如下代码: List<String> list = new ArrayList<String>(); list.add("1" ...
SQL语句笔记/好记性不如烂笔头/持续更新
常用的增删改查操作,针对库,表,字段,记录分类有助于记忆,当然熟能生巧,还是需要多多实操库操作删除库 drop database dbx; 列出所有库 show databases; 切换库 us ...
SQL,Linq,Lambda之间的转换练习
1.查询Student表中的所有记录的Sname.Ssex和Class列. SQL:select sname,ssex,class from Students linq:from s in Stude ...
sql linq lambda 对比
. 查询Student表中的所有记录的Sname.Ssex和Class列. select sname,ssex,class from student Linq: from s in Students ...
好记性不如烂笔头-linux学习笔记5mysql主从复制
mysql主从复制的原理 mysql master服务器,开启bin-log日志,开启IO线程 slave服务器,开启IO线程,开启SQL线程(执行SQL) 1)slave服务器,通过授权用户开启IO ...

随机推荐

MongoDB 1: NoSQL 和 SQL的区别
导读:本篇博客,主要是结合自己在项目中的使用,简单的阐述一下NoSQL和SQL的区别.那么,根据自己的应用,NoSQL这边,选择的是MongoDB(Redis虽然也是,但属于内存存储,这里不予说明). ...
正斜杠和反斜杠-windows、web、c语言大讨论
首先,在c语言中,正斜杠/ slash 表示除法反斜杠\ backslash ,\用于转义字符,\n.\0. 其次,UNIX 操作系统设计了这种路径分隔法,它使用正斜杠:/.由于网络是首先应用在 UN ...
Delphi Form的释放和隐藏：free,hide,close
form.Free - 释放Form占用的所有资源.Free后,Form指针不能再使用,除非对Form重新赋值. form.Hide - 隐藏Form.可以调用form.Show再 ...
Magento修改css样式更新之——grunt命令使用
1.清除pub/static和var中相应文件 2.源头文件重新导入pub/static 3.pub中的less编译 4.字面翻译是跟踪源头文件变化实时编译,但是这里的the source files ...
Magento后台界面全局样式修改之——font-weight
路径: \app\design\adminhtml\Magento\backend\web\app\setup\styles\less\lib\_variables.less
[视频]物联网应用-ARM mbed-来至MultiTech Systems的解决方案
ARM公司面向物联网及可穿戴市场,近期可谓是动作频频,先是发布了专为物联网及可穿戴领域而生的Cortex-M7架构,接着又发布了mbed物联网操作系统.意图在物联网领域构筑一套坚不可摧的生态系统. 这 ...
sqlserver 保留小数方法
1. 使用 Round() 函数,如 Round(@num,2) 参数 2 表示保留两位有效数字. 2. 更好的方法是使用 Convert(decimal(18,2),@num) 实现转换,dec ...
Centos 7.1+CDH5.7.2全部署流程
前期准备: JDK环境版本:jdk-8u101-linux-x64.rpm 下载地址:oracle官网 mysql rpm包:http://dev.mysql.com/get/Downloads/M ...
分享：php 上传图片的代码
转自:http://www.jbxue.com/article/6379.html php 上传图片的代码,很简单,实现了基本的文件类型.文件大小的检测,并实现了基本的水印与缩略功能,比较适合初学的朋 ...
【Window】Tor（洋葱头路由）+Privoxy 网络实践（附带Java实例代码）
1.背景平时我们需要访问onion后缀的网站,需要通过Tor(The Onion Router,洋葱路由器).一般来说安装Tor Broswer就可以满足需要.但是项目我要做的是通过程序来获取oni ...

SQL-LINQ-Lambda语法对照，好记性不如烂笔头

SQL-LINQ-Lambda语法对照，好记性不如烂笔头的更多相关文章

随机推荐

热门专题