欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识!
您现在的位置是: 首页  >  数据库

atitit.判断时间重叠方法总结javac++c#.netjsphp

程序员文章站 2024-01-02 12:47:28
...

atitit.判断时间重叠方法总结 java c++ c#.net js php 1. 判断时间重叠具体流程思路 1 2. 重叠算法 实际上就是日期集合跟个时间集合的的交集(乘法算法) 1 3. 代码--- 1 4. 最终生成的sql 3 5. 参考 5 1. 判断时间重叠具体流程思路 先判断日期重叠,在判断时

atitit.判断时间重叠方法总结 java c++ c#.net js php

1. 判断时间重叠具体流程思路 1

2. 重叠算法 实际上就是日期集合跟个时间集合的的交集(乘法算法) 1

3. 代码--- 1

4. 最终生成的sql 3

5. 参考 5

1. 判断时间重叠具体流程思路

先判断日期重叠,在判断时间区段重叠。

每个区段都有内包含,外包含,左包含,右包括...所以,or表达式需要4*4=16个..每个or 表达式包括4个and表达式( 两个日期表达式,两个时间范围表达式)

最终的最终的的表达式需要16*4=64个,,比较长的了..

2. 重叠算法 实际上就是日期集合跟个时间集合的的交集(乘法算法)

在程序设计里有。。。。。

回答

那实际上就是交、并、差。
所谓加,实际上就是求两个集合的并集
减,就是求两个集合的差集
乘,就是求两个集合的并集
它们都是从逻辑的运算推出来的

另外更正一下:乘是求两个集合的交集。

3. 代码---

private void ini() {

String db_start_fld = "start_time";

String db_end_fld = "end_time";



String db_include_exp = "db_start_fld>=ui_start and db_end_fld=ui_end ";

String db_leftinclude_exp = "db_end_fld>=ui_start and db_end_fld =ui_start and db_end_fld dateExpList = new ArrayList() {

{



add(expandFunc(db_include_exp));

add(expandFunc(db_outclude_exp));

add(expandFunc(db_leftinclude_exp));

add(expandFunc(db_ritinclude_exp));



}



private String expandFunc(String db_include_exp) {

String db_start_fld_Datefunc = " CONVERT(varchar(100), db_start_fld, 23)";

String db_end_fld_Datefunc = " CONVERT(varchar(100), db_end_fld, 23)";

return db_include_exp.replaceAll("db_start_fld",

db_start_fld_Datefunc).replaceAll("db_end_fld",

db_end_fld_Datefunc);

}

};





List timeExpList = new ArrayList() {

{

add(expandFunc(db_include_exp));

add(expandFunc(db_outclude_exp));

add(expandFunc(db_leftinclude_exp));

add(expandFunc(db_ritinclude_exp));



}



private String expandFunc(String db_include_exp) {

String db_start_fld_Timefunc = " CONVERT(varchar(100), db_start_fld, 8)";

String db_end_fld_Timefunc = " CONVERT(varchar(100), db_end_fld, 8)";

return db_include_exp.replaceAll("db_start_fld",

db_start_fld_Timefunc).replaceAll("db_end_fld",

db_end_fld_Timefunc);

}

};



List finalList= new ArrayList() {{



for (String dateExp : dateExpList) {

for (String timeExp : timeExpList) {

this.add(dateExp+" and "+timeExp.replaceAll("db_start_fld", db_start_fld).replaceAll("db_end_fld", db_end_fld));

}

}



}};



String sql=new ArrayList(){

private String exec( ) {

String exp_final=" 1=1 ";

for (String exp : finalList) {

//if(exp_final.length()==0)

exp_final=exp_final + " or ( "+exp +" ) ";

}

return exp_final;



}}.exec( );

System.out.println(sql);





}

4. 最终生成的sql


SELECT *

FROM tab

WHERE 1=1

OR (CONVERT(varchar(100), db_start_fld, 23)>=ui_start

AND CONVERT(varchar(100), db_end_fld, 23)=ui_start

AND CONVERT(varchar(100), end_time, 8)=ui_start

AND CONVERT(varchar(100), db_end_fld, 23)=ui_end)

OR (CONVERT(varchar(100), db_start_fld, 23)>=ui_start

AND CONVERT(varchar(100), db_end_fld, 23)=ui_start

AND CONVERT(varchar(100), end_time, 8) =ui_start

AND CONVERT(varchar(100), db_end_fld, 23)=ui_start

AND CONVERT(varchar(100), end_time, 8)=ui_end

AND CONVERT(varchar(100), start_time, 8)>=ui_start

AND CONVERT(varchar(100), end_time, 8)=ui_end

AND CONVERT(varchar(100), start_time, 8)=ui_end)

OR (CONVERT(varchar(100), db_start_fld, 23)=ui_end

AND CONVERT(varchar(100), end_time, 8)>=ui_start

AND CONVERT(varchar(100), end_time, 8) =ui_end

AND CONVERT(varchar(100), start_time, 8)>=ui_start

AND CONVERT(varchar(100), end_time, 8)=ui_start

AND CONVERT(varchar(100), db_end_fld, 23) =ui_start

AND CONVERT(varchar(100), end_time, 8)=ui_start

AND CONVERT(varchar(100), db_end_fld, 23) =ui_end)

OR (CONVERT(varchar(100), db_end_fld, 23)>=ui_start

AND CONVERT(varchar(100), db_end_fld, 23) =ui_start

AND CONVERT(varchar(100), end_time, 8) =ui_start

AND CONVERT(varchar(100), db_end_fld, 23) =ui_start

AND CONVERT(varchar(100), end_time, 8)=ui_start

AND CONVERT(varchar(100), db_end_fld, 23)=ui_start

AND CONVERT(varchar(100), end_time, 8)=ui_start

AND CONVERT(varchar(100), db_end_fld, 23)=ui_end)

OR (CONVERT(varchar(100), db_start_fld, 23)>=ui_start

AND CONVERT(varchar(100), db_end_fld, 23)=ui_start

AND CONVERT(varchar(100), end_time, 8) =ui_start

AND CONVERT(varchar(100), db_end_fld, 23)=ui_start

AND CONVERT(varchar(100), end_time, 8)

上一篇:

下一篇: