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
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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_outclude_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_end ";
String db_ritinclude_exp = "db_start_fld>=ui_start and db_end_fld<=ui_end ";
List<String> dateExpList = new ArrayList<String>() {
{
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<String> timeExpList = new ArrayList<String>() {
{
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<String> finalList= new ArrayList<String>() {{
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_end AND CONVERT(varchar(100), start_time, 8)>=ui_start AND CONVERT(varchar(100), end_time, 8)<=ui_end) OR (CONVERT(varchar(100), db_start_fld, 23)>=ui_start AND CONVERT(varchar(100), db_end_fld, 23)<=ui_end AND CONVERT(varchar(100), start_time, 8)<=ui_start AND CONVERT(varchar(100), end_time, 8)>=ui_end) OR (CONVERT(varchar(100), db_start_fld, 23)>=ui_start AND CONVERT(varchar(100), db_end_fld, 23)<=ui_end AND CONVERT(varchar(100), end_time, 8)>=ui_start AND CONVERT(varchar(100), end_time, 8) <=ui_end) OR (CONVERT(varchar(100), db_start_fld, 23)>=ui_start AND CONVERT(varchar(100), db_end_fld, 23)<=ui_end AND CONVERT(varchar(100), start_time, 8)>=ui_start AND CONVERT(varchar(100), end_time, 8)<=ui_end) OR (CONVERT(varchar(100), db_start_fld, 23)<=ui_start AND CONVERT(varchar(100), db_end_fld, 23)>=ui_end AND CONVERT(varchar(100), start_time, 8)>=ui_start AND CONVERT(varchar(100), end_time, 8)<=ui_end) OR (CONVERT(varchar(100), db_start_fld, 23)<=ui_start AND CONVERT(varchar(100), db_end_fld, 23)>=ui_end AND CONVERT(varchar(100), start_time, 8)<=ui_start AND CONVERT(varchar(100), end_time, 8)>=ui_end) OR (CONVERT(varchar(100), db_start_fld, 23)<=ui_start AND CONVERT(varchar(100), db_end_fld, 23)>=ui_end AND CONVERT(varchar(100), end_time, 8)>=ui_start AND CONVERT(varchar(100), end_time, 8) <=ui_end) OR (CONVERT(varchar(100), db_start_fld, 23)<=ui_start AND CONVERT(varchar(100), db_end_fld, 23)>=ui_end AND CONVERT(varchar(100), start_time, 8)>=ui_start AND CONVERT(varchar(100), end_time, 8)<=ui_end) OR (CONVERT(varchar(100), db_end_fld, 23)>=ui_start AND CONVERT(varchar(100), db_end_fld, 23) <=ui_end AND CONVERT(varchar(100), start_time, 8)>=ui_start AND CONVERT(varchar(100), end_time, 8)<=ui_end) OR (CONVERT(varchar(100), db_end_fld, 23)>=ui_start AND CONVERT(varchar(100), db_end_fld, 23) <=ui_end AND CONVERT(varchar(100), start_time, 8)<=ui_start AND CONVERT(varchar(100), end_time, 8)>=ui_end) OR (CONVERT(varchar(100), db_end_fld, 23)>=ui_start AND CONVERT(varchar(100), db_end_fld, 23) <=ui_end AND CONVERT(varchar(100), end_time, 8)>=ui_start AND CONVERT(varchar(100), end_time, 8) <=ui_end) OR (CONVERT(varchar(100), db_end_fld, 23)>=ui_start AND CONVERT(varchar(100), db_end_fld, 23) <=ui_end AND CONVERT(varchar(100), start_time, 8)>=ui_start AND CONVERT(varchar(100), end_time, 8)<=ui_end) OR (CONVERT(varchar(100), db_start_fld, 23)>=ui_start AND CONVERT(varchar(100), db_end_fld, 23)<=ui_end AND CONVERT(varchar(100), start_time, 8)>=ui_start AND CONVERT(varchar(100), end_time, 8)<=ui_end) OR (CONVERT(varchar(100), db_start_fld, 23)>=ui_start AND CONVERT(varchar(100), db_end_fld, 23)<=ui_end AND CONVERT(varchar(100), start_time, 8)<=ui_start AND CONVERT(varchar(100), end_time, 8)>=ui_end) OR (CONVERT(varchar(100), db_start_fld, 23)>=ui_start AND CONVERT(varchar(100), db_end_fld, 23)<=ui_end AND CONVERT(varchar(100), end_time, 8)>=ui_start AND CONVERT(varchar(100), end_time, 8) <=ui_end) OR (CONVERT(varchar(100), db_start_fld, 23)>=ui_start AND CONVERT(varchar(100), db_end_fld, 23)<=ui_end AND CONVERT(varchar(100), start_time, 8)>=ui_start AND CONVERT(varchar(100), end_time, 8)<=ui_end)
