atitit.判断时间重叠方法总结javac++c#.netjsphp

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)