左外连接(Left Outer Join)是一种数据库查询操作,它返回左表中所有记录的数据,即使右表中没有匹配的记录。在LINQ to SQL中,左外连接可以使用DefaultIfEmpty()方法来实现。 以下是一个使用LINQ to SQL实现左外连接的示例代码: 代码语言:csharp 复制 var leftOuterJoinQuery = from left in db.LeftTable join r...
生成SQL语句为: SELECT[t0].[ProductID],[t0].[ProductName],[t0].[SupplierID],[t0].[CategoryID],[t0].[QuantityPerUnit],[t0].[UnitPrice],[t0].[UnitsInStock],[t0].[UnitsOnOrder],[t0].[ReorderLevel],[t0].[Discontinued]FROM[dbo].[Products]AS[t0]LEFTOUTERJOIN[dbo].[Suppliers]AS[t1...
[t0].[QuantityPerUnit],[t0].[UnitPrice], [t0].[UnitsInStock], [t0].[UnitsOnOrder],[t0].[ReorderLevel], [t0].[Discontinued] FROM [dbo].[Products] AS [t0] LEFT OUTER JOIN [dbo].[Suppliers] AS [t1] ON [t1].[SupplierID] = [t0].[SupplierID] WHERE ([t1].[Country] =...
这个Linq to sql 语句生成的对应 SQL 为: exec sp_executesql N'SELECT [t0].[Id] AS [RoleId], [t0].[Name] AS [RoleName], (CASE WHEN [t2].[test] IS NOT NULL THEN 1 ELSE 0 END) AS [IsSet] FROM [Role] AS [t0] LEFT OUTER JOIN ( SELECT 1 AS [test], [t1...
对应的SQL: SELECT [t1].[ID], [t1].[CustomerID], [t1].[Date], [t1].[Description], [t1].[Price], ( SELECT COUNT(*) FROM [Purchase] AS [t2] WHERE ([t0].[ID]) = [t2].[CustomerID] ) AS [value], [t0].[Name] FROM [Customer] AS [t0] LEFT OUTER JOIN [Purchase] AS [...
SQL中常见的连接查询有: left join: 左连接,返回左表中所有的记录以及右表中连接字段相等的记录。 right join: 右连接,返回右表中所有的记录以及左表中连接字段相等的记录。 inner join: 内连接,又叫等值连接,只返回两个表中连接字段相等的行。 full join: 外连接,返回两个表中的行:left join + right join...
这个Linqtosql语句生成的对应SQL为: execsp_executesqlN'SELECT[t0].[Id]AS[RoleId],[t0].[Name]AS[RoleName], (CASE WHEN[t2].[test]ISNOTNULLTHEN1 ELSE0 END)AS[IsSet] FROM[Role]AS[t0] LEFTOUTERJOIN( SELECT1AS[test],[t1].[StaffId],[t1].[RoleId] ...
[t0].[Discontinued]FROM[dbo].[Products]AS[t0]LEFT OUTER JOIN[dbo].[Suppliers]AS[t1]ON[t1].[SupplierID] = [t0].[SupplierID]WHERE([t1].[Country] = @p0)AND([t0].[UnitsInStock] = @p1)-- @p0: Input NVarChar (Size = 3; Prec = 0; Scale = 0) [USA] ...
Join with max in LINQ to SQL Keyword not supported: ',server'. Left outer join with Linq and multiple join conditions LIKE operator for BIGINT data type LINQ - Row not found or changed (yet it is a simple/direct attempt to save) ...
每個客戶物件都有一個屬性,包含該客戶所有訂單的集合。 下列程式碼範例顯示的查詢運算式,結合了階層式結果的客戶和訂單資料,並傳回匿名類型的集合。 查詢傳回的類型包含CustomerOrders屬性,內含客戶訂單資料的集合。 它也包含OrderTotal屬性,內含該客戶所有訂單小計的總和。 (這個查詢相當於 LEFT OUTER JOIN)。