Oracle的overlaps函數轉換其他數據庫語法

首先，來介紹一下Oracle的overlaps函數的用法：

overlaps函數是用來判斷兩個時間段是否有重疊的

比如說計算 (a,b),(c,d)

就可以寫成：

select * from dual where (a,b) overlaps (c,d);

其中abcd都是日期格式。

注意：比較的只能是日期。如果是數字，則會報錯 ORA-00932: inconsistent datatypes

 

最近項目在使用db2數據庫，遇到overlaps函數需要轉換成db2中的語法方言，其實就是轉換為通用的sql語法。

 

對應的寫法有：

判斷兩個時間段是否有重疊

(a,b),(c,d)

判斷兩段時間是否有重疊

方法一

select 'yes' from dual where d>a and c<b;

例子：

select *
from PMK_PLANNING_INFO
where id = 'U2KsqII5NdumrClO5td'
and to_date('2019/07/27', 'YYYY/MM/DD') > to_date(begin_time)
and to_date('2018/06/27', 'YYYY/MM/DD') < to_date(end_time);

方法二

select 'yes' from dual where (a, b) overlaps (c,d);

例子：

select *
from PLANNING_INFO
where id = '001'
and (to_date(begin_time), to_date(end_time))
overlaps
(to_date('2018/06/27', 'YYYY/MM/DD'),
to_date('2019/07/27', 'YYYY/MM/DD'));

方法三

select 'yes' from dual where a between c and d or d between a and b;

例子：

select *
from PMK_PLANNING_INFO
where id = 'U2KsqII5NdumrClO5td'
and to_date(begin_time) between to_date('2018/06/27', 'YYYY/MM/DD') and to_date('2019/07/27', 'YYYY/MM/DD')
or to_date('2019/07/27', 'YYYY/MM/DD') between to_date(begin_time) and to_date(end_time);

a ： to_date(begin_time)

b ：to_date(end_time)

c ：to_date('2018/06/27', 'YYYY/MM/DD')

d ：to_date('2019/07/27', 'YYYY/MM/DD')