比如,我要建立一个1,000,000行的数字表: CREATE TABLE dbo.Nums(n INT NOT NULL PRIMARY KEY); DECLARE @max AS INT, @rc AS INT; SET @max = 1000000; SET @rc = 1; INSERT INTO Nums VALUES(1); WHILE @rc * 2 <= @max BEGIN INSERT INTO dbo..
Select字句在逻辑上是SQL语句最后进行处理的最后一步,所以,以下查询会发生错误:SELECT YEAR(OrderDate) AS OrderYear, COUNT(DISTINCT CustomerID) AS NumCustsFROM dbo.OrdersGROUP BY OrderYear;因为group by是在Select之前进行的,那个时候or..
AD HOC PAGING:就是指用页面的序号和页面的大小请求一个单独的页面。下面是例子。DECLARE @pagesize AS INT, @pagenum AS INT;SET @pagesize = 5;SET @pagenum = 2;WITH SalesCTE AS( SELECT ROW_NUMBER() OVER(ORDER BY qty, empid) AS rownum,em..
SQL2005增加了4个关于队计算的函数:分别是ROW_NUMBER,RANK,DENSE_RANK,NTILE.注意:这些函数只能出现在SELECT和ORDER BY的查询中。语法如下:ranking_function over([partition by col_list] order by col_list)ROW_NUMBER:在排序的基础上对所有列..
复制代码 代码如下:TRUNCATE TABLE (Transact-SQL)Removes all rows from a table without logging the individual row deletions. TRUNCATE TABLE is similar to the DELETE statement with no WHERE clause; however, TRUNCATE TABLE is faster a..