2)SELECT语句中有DISTINCT的话,ORDER BY的字段必须在SELECT中,下面的语句错误 SELECTDISTINCTcountryFROMHR.EmployeesORDERBYempid; 4,TOP 语句 1)TOP可以指定PERCENT,返回所有记录的百分比 SELECTTOP(1)PERCENTorderid, orderdate, custid, empidFROMSales.OrdersORDERBYorderdateDESC; 2)TOP后加入WITH TIES选项的话,会...
TOP选项是一个专有的T-SQL功能,用于限制查询返回的行数或行的百分比。SELECT TOP (1) PERCENT orderid, orderdate, custid, empidFROM Sales.OrdersORDER BY orderdate DESC;2 OFFSET-FETCH筛选TOP选项不是标准SQL,且不支持跳过功能,OFFSET-FETCH是标准SQL,SQL Server2012时引入。SELECT orderid, orderdate, cust...
you can now request to wait for a T-SQL statement to affect at least one row. You can specify that the command wait on one of the following statements: SELECT, INSERT, UPDATE, DELETE, or RECEIVE. The first four are self-explanatory; RECEIVE refers to receiving a message from a queue....
A function to map each source element to an element in an IGrouping<TKey, TElement>. resultSelector Type: System.Linq.Expressions.Expression<Func<TKey, IEnumerable<TElement>, TResult>> A function to create a result value from each group. comparer Type: System.Collections.Generic.IEqualityCompa...
ObjectQuery<Product> productQuery1 = new ObjectQuery<Product>("Products", context); foreach (Product result in productQuery1) Console.WriteLine("Product Name: {0}", result.Name); string queryString = @"SELECT VALUE product FROM AdventureWorksEntities.Products AS product"; // Call the constructo...
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derived_table can use the Transact-SQL table value constructor feature to specify multiple rows. For example, SELECT * FROM (VALUES (1, 2), (3, 4), (5, 6), (7, 8), (9, 10) ) AS MyTable(a, b);. For more information, see Table Value Constructor (Transact-SQL)....
SELECT CAST(SYSDATETIME() AS DATE) AS [current_date], CAST(SYSDATETIME() AS TIME) AS [current_time]; Interestingly, when converting a column whose data type contains both a date and a time component to DATE, the SQL Server query optimizer can still rely on index ordering to process a ...
ServerGroup1', @target_type = 'SqlServer', @server_name = 'server1.database.windows.net';--View the recently created target group and target group membersSELECT*FROMjobs.target_groupsWHEREtarget_group_name='ServerGroup1';SELECT*FROMjobs.target_group_membersWHEREtarget_group_name='ServerGroup1'...
(IQueryable<TSource>, Expression<Func<TSource, TKey>>, IEqualityComparer<TKey>) depends on the implementation of the type of the source parameter. The expected behavior is that it groups the elements of source by a key value. The key value is obtained by invoking keySelector on...