使用OFFSET-FETCH进行数据过滤

TOP的工业标准版 OFFSET-FETCH

OFFSET 用来设置跳过行的数量 FETCH 用来设置检索多少行，必须要排序才能用，SQL Server 2012的新语法

从语意的角度来讲如果要跳开几行，那么你用关键词 FETCH NEXT，如果不跳过任何行。则使用FETCH FIRST 。（也就是说这两个是一个意思？ 有其他区分请告诉我。。）

-- skip 50 rows, fetch next 25 rows
SELECT orderid, orderdate, custid, empid
FROM Sales.Orders
ORDER BY orderdate DESC, orderid DESC
OFFSET 50 ROWS FETCH NEXT 25 ROWS ONLY;

-- fetch first 25 rows
SELECT orderid, orderdate, custid, empid
FROM Sales.Orders
ORDER BY orderdate DESC, orderid DESC
OFFSET 0 ROWS FETCH FIRST 25 ROWS ONLY;

-- skip 50 rows, return all the rest
SELECT orderid, orderdate, custid, empid
FROM Sales.Orders
ORDER BY orderdate DESC, orderid DESC
OFFSET 50 ROWS;

-- ORDER BY is mandatory; return some 3 rows
SELECT orderid, orderdate, custid, empid
FROM Sales.Orders
ORDER BY (SELECT NULL)
OFFSET 0 ROWS FETCH FIRST 3 ROWS ONLY;
GO

-- 分页
DECLARE @pagesize AS BIGINT = 25, @pagenum AS BIGINT = 3;

SELECT orderid, orderdate, custid, empid
FROM Sales.Orders
ORDER BY orderdate DESC, orderid DESC
OFFSET (@pagenum - 1) * @pagesize ROWS FETCH NEXT @pagesize ROWS ONLY;
GO