如何在列数据发生变化时获取行

Question

我有下面的表格

Id  | Status | date
-------------------
1   | Onsite |2007
2   | Onsite |2008
3   | Onsite |2009
4   | Abroad |2010
5   | Abroad |2011
6   | Onsite |2012
7   | Abroad |2013
8   | Abroad |2014
9   | Onsite |2015

我想要一个在MySQL中的查询，当状态从‘国外’变为‘现场’时，它会返回一条记录。在上述情况下，查询将返回以下行：

6  | Onsite |2012
9  | Onsite |2015

Answer 1

尝试执行以下查询，即使in不在序列中也能正常工作：

SELECT * 
FROM 'table_name' t
WHERE t.status = 'Onsite' and 
       EXISTS(SELECT t1.id 
               FROM 'table_name' t1 
               WHERE t1.status = 'Abroad' and t1.id<t.id
               ORDER BY t1.id DESC 
               LIMIT 1,1);