zoukankan      html  css  js  c++  java
  • 几条高效的分页语句

    1.使用 ROW_NUMBER() OVER 的分页查询

    SELECT *
    FROM
    (
    SELECT *, ROW_NUMBER() OVER (ORDER BY id asc) as rowNum
    FROM memberLevel
    ) AS T
    WHERE T.RowNum>=0 and T.RowNum<= 2

    相应语法:

    转自:http://www.cnblogs.com/icebutterfly/archive/2009/08/05/1539657.html

    语法:ROW_NUMBER() OVER(PARTITION BY COLUMN ORDER BY COLUMN)

    简单的说row_number()从1开始,为每一条分组记录返回一个数字,这里的ROW_NUMBER() OVER (ORDER BY xlh DESC) 是先把xlh列降序,再为降序以后的没条xlh记录返回一个序号。 
    示例: 
    xlh           row_num 
    1700              1 
    1500              2 
    1085              3 
    710                4

    row_number() OVER (PARTITION BY COL1 ORDER BY COL2) 表示根据COL1分组,在分组内部根据 COL2排序,而此函数计算的值就表示每组内部排序后的顺序编号(组内连续的唯一的)

    实例:

    初始化数据

    create table employee (empid int ,deptid int ,salary decimal(10,2))
    insert into employee values(1,10,5500.00)
    insert into employee values(2,10,4500.00)
    insert into employee values(3,20,1900.00)
    insert into employee values(4,20,4800.00)
    insert into employee values(5,40,6500.00)
    insert into employee values(6,40,14500.00)
    insert into employee values(7,40,44500.00)
    insert into employee values(8,50,6500.00)
    insert into employee values(9,50,7500.00)

    数据显示为

    empid       deptid      salary
    ----------- ----------- ---------------------------------------
    1           10          5500.00
    2           10          4500.00
    3           20          1900.00
    4           20          4800.00
    5           40          6500.00
    6           40          14500.00
    7           40          44500.00
    8           50          6500.00
    9           50          7500.00

    需求:根据部门分组,显示每个部门的工资等级

    预期结果:

    empid       deptid      salary                                  rank
    ----------- ----------- --------------------------------------- --------------------
    1           10          5500.00                                 1
    2           10          4500.00                                 2
    4           20          4800.00                                 1
    3           20          1900.00                                 2
    7           40          44500.00                                1
    6           40          14500.00                                2
    5           40          6500.00                                 3
    9           50          7500.00                                 1
    8           50          6500.00                                 2

    SQL脚本:

    SELECT *, Row_Number() OVER (partition by deptid ORDER BY salary desc) rank FROM employee

  • 相关阅读:
    CSS浮动(float、clear)通俗讲解
    JAVA 类的加载
    数据库操作 delete和truncate的区别
    正则表达式 匹配相同数字
    Oracle EBS OM 取消订单
    Oracle EBS OM 取消订单行
    Oracle EBS OM 已存在的OM订单增加物料
    Oracle EBS OM 创建订单
    Oracle EBS INV 创建物料搬运单头
    Oracle EBS INV 创建物料搬运单
  • 原文地址:https://www.cnblogs.com/cxyzl/p/2589718.html
Copyright © 2011-2022 走看看