T_SQL 2008 语言基础学习笔记

1 ROW_NUMBER() OVER()PARTION BY COLUM ORDER BY COLUM 函数的用法：

SELECT ROW_NUMBER()OVER(ORDER BY FholidayTypeid DESC) AS ROW_ID,* FROm HR_ATS_Holiday

---目的：自动生成行号 ，以flevel 分组 ，以Fname 排序

SELECT * FROM

(SELECT ROW_NUMBER()OVER(PARTITION BY FleveL ORDER BY Fname) AS ROW_ID,* FROM t_account)t

WHERE T.ROW_ID IN(1,2)

--作用介绍：可以用来删除重复数据。PARTITION BY 后边是分组字段，分组后利用row_number 函数记录处

--每个分组行数的ID。

SELECT FLevel,COUNT(1) FROM t_Account GROUP BY FLevel HAVING COUNT(*)>100

--作用：HAVING COUNT(*) 大于多少行。。。

DELETE t FROM

(SELECT ROW_NUMBER()OVER(PARTITION BY FleveL ORDER BY Fname) AS ROW_ID,* FROM t_account)t

WHERE T.ROW_ID IN(1,2)AND FAccountID=1282